MTG Salvation

Amazing deck! I am planning to build it - and it'll be the first non-pauper EDH for me
I will start with your budget deck with a slightly different mana base and more ramp & land search.
But I would like to say I wouldn't play Whispers of the Muse and Stonecloaker. Buyback and reusability of these cards are as annoying as Capsize IMO. I'd stick with both pulses only. Oh, and some flashback spells too.
What do you think about Noxious Revival? You can reuse anything on your graveyard (counter, destroyed land, etc) or wreck some renimate effect. I will test this one.When I assemble my deck in my mind I will post it here.
Congrats for now!

The beauty of this deck is that it doesn't really require specific cards other than the commander, only that they fit styles like: counter, recursion, draw, mass removal, etc.
Stonecloaker is one of the better targeted gy removals since it is repeatable but you can just go for some mass gy removal or your own version of gy removal, as long as it replaces that job of gy control. It's just hard to find something with that strength and repeatability.
Noxious Revival is very strong and worth considering in any build similar to the original due to what you mentioned. Regrowth I feel is a bit stronger due to same-turn plays like Regrowth into Wrath of God-variant, but both are good and including both is a good choice as well.

I don't think there's much of a case to include ramp since we're not ramping to anything in particular, and they're dead draws late. The only ones I like are exploration and Burgeoning since they let us empty our hand of lands to keep it lean and mean, and they have a super low cmc and are backup targets for any tutors that hit telepathy. But that's just my two cents.

Whispers of the muse (and other repeatable draw like arch of orazca) I think circumvent the "don't play repeatable effects" rule because the result of them is both undetermined and separated from the actual board-state change, so they're significantly less threatening. With capsize your opponents know exactly how much havoc you can wreak and will play accordingly. Also to get value out of capsize you have actually bounce permanents, which is bound to make people mad. If you're just playing whispers, you don't need to piss anyone off to get value. You also can just not cast it when you're already at 7 cards. And, like all buyback spells, if it's becoming a problem you can always just cast it without buyback. I haven't played whispers a whole lot, but arch has been consistently excellent and they're very similar effects.

Stonecloaker is a different beast and I do wish we had a better tool for the job. Being a creature makes it a target for otherwise-useless removal, and being a repeatable hate card against graveyard decks can put us in the position of being a threat to those players and is likely to attract their attention. But graveyard based decks can be difficult for us to deal with, and having a single-use grave-hate like clear the mind can only delay the problem. I've been using stonecloaker in most version of phelddagrif and my main strategy with it has been to be very judicious about how you use it - don't eot it constantly for value, only use it when you absolutely have to and be apologetic about it. But YMMV, it's definitely one of the least on-brand cards in the deck. If you wanted an alternative, I think perhaps the best option might be including a bunch of deserts alongside scavenger grounds (which already merits a spot) so that you have repeatable, but not unlimited and not without a real cost, grave hate. That way your judicious use of the effect is more explicable as not wanting to lose your lands and not wanting to use your answers against subpar targets, rather than just being permissive for no reason. The deserts could also help speed up the phelddagrif clock by a turn or two, or give some cycling in the late-game, so it's not a bad solution. Even the mill one could be useful as a weak alt wincon. Hmm, I might have talked myself into it. You'd probably want to make sure you have some land tutors, though.

Flashback is great but there aren't a ton of flashback spells that fit in the deck unfortunately. Deep analysis is a decent draw spell. Fervent Denial is the wrong kind of card to have revealed in your grave, same for divine reckoning, both will have people trying to bait you into firing them off. flash of insight is also decent. memory's journey/krosan reclamation are both ok grave hate/anti-mill tech and can be played. moment's peace is great. prismatic strands is an ok backup but significantly worse in several ways. purify the grave is too low-impact imo, I'd rather have memory's journey. ray of distortion is really overpriced. ray of revelation is too narrow. think twice does too little imo, it's fine but I'd just play a bigger draw spell. aaaand that's all of them. Some ok but replaceable draw, some decent grave hate, and one excellent fog.

Noxious revival has the downside of being effectively sorcery speed when used on yourself (unless you have an instant-speed way to draw it), which makes it a bad choice for recurring counterspells, and really only great for recurring board wipes and our scant few permanents, and even then you're down a card. Unfortunately I don't think there are any ways to recur to hand at instant speed, unless you count reap, which is pretty sketchy (although a very high ceiling, obviously, maybe even too high to be honest). As far as the tempo play of putting a reanimation target on their deck, we're more in the business of value plays instead of tempo plays, so I'd much prefer to exile it than delay the inevitable.

Anyway those are my thoughts, I hope you enjoy the deck!

OK, so for some fun I took a look at all the deserts we can run in the deck and I'll run through them and offer some opinions real quick.

cradle of the accursed -
Not really what we're looking for. If it was an instant at least we could have a flash blocker in an emergency.

Desert -
Not a totally useless ability, could screw with some combat math and kills hippo tokens gone rogue, and it's a nice low cost. Obviously better if you've got good fixing.

desert of the indomitable/desert of the mindful/desert of the true -
I like these a decent amount, they have that low-powered-new-card stink that makes a deck really look like a piece of crap worthy of being ignored And realistically paying 1 more for cycling is pretty irrelevant at the point you'd be cycling them. LFTL interaction is obviously...questionable. Might be too strong, or maybe the extra cost makes it ok. I haven't run lftl in a while though.

dunes of the dead -
This does give us a flash blocker when in combo with one of the sac deserts. Better than cradle since we'd basically never sac cradle to itself. Still mostly useless, though.

Endless Sands -
Solid card but, at least for my current version it doesn't really do anything. Protect stonecloaker, which we're trying to make obselete? lol. Good if you have a decent number of creatures, but that's really stretching the boundaries of this deck.

Grasping dunes -
I guess it's removal for some small number of things, but being a sorcery I'm pretty not into it. OG desert seems a lot better, even if this can ignore combat.

Hashep Oasis -
Speeds up phelddagrif by 1 turn by itself, 2 turns with a buddy desert. Plus it taps for green and is untapped, but doesn't have to hurt us, so the cost is really low. Definitely the best of the utility lands imo.

Hostile Desert -
If we do have a bunch of deserts like the cyclers this could conceivably activate, but other than chumping it's pretty useless.

Ipnu Rivulet -
Comes at a low cost like hashep oasis, but its effect is a lot weaker. Still, could be a way to mill people out, if you have enough deserts and the game is super long.

Painted Bluffs -
Definitely worse than a basic, but it's not the worst land ever fixing-wise. Probably better than a colorless land with no useful abilities at all, like cradle or grasping dunes.

Scavenger Grounds -
Obviously great.

Shefet Dunes -
Same low cost as the others, but it's a 1-turn speed increase for Phelddagrif and that's it. Still pretty solid though.

Sunscorched desert -
Does nothing except slightly annoy someone. No thanks.

Survivor's Encampment -
On the plus side, Phelddagrif is almost always untapped so you have an easy way to fix, but you already need all 3 colors of mana to cast Phelddagrif. Probably worse than painted bluffs on balance.

OK, so after all that, I think the deserts worth playing are:

• scavenger grounds (duh)
  
• desert of the indomitable
  
• desert of the mindful
  
• desert of the true
  
• hashep oasis
  
• Shefet Dunes
  
• Ipnu Rivulet (maybe)
  
• Desert (maybe)

I think that gives us enough that we should reasonably expect to draw a couple at least, over the course of a game, and more if we're determined.

I don't think there's much of a case to include ramp since we're not ramping to anything in particular, and they're dead draws late. The only ones I like are exploration and Burgeoning since they let us empty our hand of lands to keep it lean and mean, and they have a super low cmc and are backup targets for any tutors that hit telepathy. But that's just my two cents.

Actually I meant land search for our utility lands using a couple spells like Sylvan Scrying. Ramp will be made using 2-3 ramping lands.

Whispers of the muse (and other repeatable draw like arch of orazca) I think circumvent the "don't play repeatable effects" rule because the result of them is both undetermined and separated from the actual board-state change, so they're significantly less threatening. With capsize your opponents know exactly how much havoc you can wreak and will play accordingly. Also to get value out of capsize you have actually bounce permanents, which is bound to make people mad. If you're just playing whispers, you don't need to piss anyone off to get value. You also can just not cast it when you're already at 7 cards. And, like all buyback spells, if it's becoming a problem you can always just cast it without buyback. I haven't played whispers a whole lot, but arch has been consistently excellent and they're very similar effects.

I agree with the threatening part. Will think about it.

Stonecloaker is a different beast and I do wish we had a better tool for the job. Being a creature makes it a target for otherwise-useless removal, and being a repeatable hate card against graveyard decks can put us in the position of being a threat to those players and is likely to attract their attention. But graveyard based decks can be difficult for us to deal with, and having a single-use grave-hate like clear the mind can only delay the problem. I've been using stonecloaker in most version of phelddagrif and my main strategy with it has been to be very judicious about how you use it - don't eot it constantly for value, only use it when you absolutely have to and be apologetic about it. But YMMV, it's definitely one of the least on-brand cards in the deck. If you wanted an alternative, I think perhaps the best option might be including a bunch of deserts alongside scavenger grounds (which already merits a spot) so that you have repeatable, but not unlimited and not without a real cost, grave hate. That way your judicious use of the effect is more explicable as not wanting to lose your lands and not wanting to use your answers against subpar targets, rather than just being permissive for no reason. The deserts could also help speed up the phelddagrif clock by a turn or two, or give some cycling in the late-game, so it's not a bad solution. Even the mill one could be useful as a weak alt wincon. Hmm, I might have talked myself into it. You'd probably want to make sure you have some land tutors, though.

Maybe the (ab)use of Scavenger Grounds is enough. Maybe the aggro-gy player will be the threat of the table abd you don't need to care that much. I will think about it but with a grain of salt.

Flashback is great but there aren't a ton of flashback spells that fit in the deck unfortunately. Deep analysis is a decent draw spell. Fervent Denial is the wrong kind of card to have revealed in your grave, same for divine reckoning, both will have people trying to bait you into firing them off. flash of insight is also decent. memory's journey/krosan reclamation are both ok grave hate/anti-mill tech and can be played. moment's peace is great. prismatic strands is an ok backup but significantly worse in several ways. purify the grave is too low-impact imo, I'd rather have memory's journey. ray of distortion is really overpriced. ray of revelation is too narrow. think twice does too little imo, it's fine but I'd just play a bigger draw spell. aaaand that's all of them. Some ok but replaceable draw, some decent grave hate, and one excellent fog.

Agree, Deep Analisys and Moment's Peace are the best options.

Noxious revival has the downside of being effectively sorcery speed when used on yourself (unless you have an instant-speed way to draw it), which makes it a bad choice for recurring counterspells, and really only great for recurring board wipes and our scant few permanents, and even then you're down a card. Unfortunately I don't think there are any ways to recur to hand at instant speed, unless you count reap, which is pretty sketchy (although a very high ceiling, obviously, maybe even too high to be honest). As far as the tempo play of putting a reanimation target on their deck, we're more in the business of value plays instead of tempo plays, so I'd much prefer to exile it than delay the inevitable.

You can always use it on opponent's EOT. And you can use Regrowth or someting like that. I like this idea of redundance, will test a couple options as well. All tests will require a tweak on mana base - I expect to have 42ish lands instead of 45.

OK, so after all that, I think the deserts worth playing are:
scavenger grounds (duh)
desert of the indomitable
desert of the mindful
desert of the true
hashep oasis
Shefet Dunes
Ipnu Rivulet (maybe)
Desert (maybe)

I will consider all colored options. Maybe an Arabian Nights Desert if I can find one Again, this is both a better way to deal with GYs (you continue under the radar) and/or pump your general more often.

Anyway those are my thoughts, I hope you enjoy the deck!

I did, I will!