I think Shrouded Lore is probably too situational, but I've also warped a Mono-B deck's manabase so that I could play Tainted Pact in Toshiro Umezawa, so I don't have room to talk. As long as you've got a commander that consistently keeps your graveyard small, or if you have a critical mass of ways to arbitrarily remove large swaths of cards from your graveyard, (Watchers of the Dead perhaps?) you could make it do what you want, but you just might have to play a bunch of other not-great cards to make it happen.
The trick doesn't actually work with Hope of Ghirapur, since after the first sacrifice, the game treats your recurred Hope of Ghirapur as a new game object that has not dealt combat damage to any player, which translates to you not being able to activate its ability because there are no valid targets for it. However, this would work with many cards that you don't have in the list like Bottle Gnomes (also arbitrary lifegain), Coretapper (more charge counters than you can shake a stick at), Lurebound Scarecrow (pick a permanent color you don't have), Phyrexian Dreadnought (lol), Thermal Navigator, or Ticking Gnomes (arbitrary damage).
I'm pretty sure this guy is like 900 times better than Kemba because his tokens can attack the turn he hits the board (instead of like, 2 full turns later) and they die to Skullclamp, which somehow has yet to be mentioned in this thread.
With at least two tokens on the field before first combat with the Fury, you get as many combat phases as cards you can draw from your library, not to mention any other shenanigans you can play from actually drawing the cards from the Bident/Piracy. Seems good to me.
Edit: I guess the main requirement here is that the tokens have to actually get through to the opponent with damage, but that shouldn't be too hard with flying and other blue things like Cyclonic Rift
Arena doesn't tap for mana without help, but it's a repeatable fight effect that most commander players don't have a way to interact with. Green also has the best tutors for lands, so you can find it with Sylvan Scrying or Crop Rotation.
With at least two tokens on the field before first combat with the Fury, you get as many combat phases as cards you can draw from your library, not to mention any other shenanigans you can play from actually drawing the cards from the Bident/Piracy. Seems good to me.
Edit: I guess the main requirement here is that the tokens have to actually get through to the opponent with damage, but that shouldn't be too hard with flying and other blue things like Cyclonic Rift
25% of the time this is much better than Nev's Disk (unless you're deliberately trying to avoid blowing up planeswalkers)
50% of the time this is basically Nev's Disk
25% of the time this is much worse than Nev's Disk.
I'd be inclined to play it in a deck that can break its symmetry or mitigate some of the variance of the coin flip, or in a deck that otherwise can't really answer certain permanent types. I think it also has a place as part of a Transmute Artifact/Reshape/Whir of Invention package as well, since it can be activated as soon as it is tutored out. Whirring for an instant speed hail Mary board wipe sounds like a lot of fun for the whole table. I'd play it in heavy artifact decks like Slobad, Goblin Tinkerer, Kurkesh, Onakke Ancient, or maybe even Arcum Dagsson, since those decks almost always play Darksteel Forge, Rings of Brighthearth, Voltaic Key, and Clock of Omens. It also has some niche uses with commanders that can animate lands.
Trying to stop everyone else in a multiplayer game from Doing The Thing is both resource intensive and annoying for everyone else for the most part.
What's your end goal here? Is it to win? If so, have you considered simply playing powerful creatures yourself instead? Is your goal to force some kind of metagame where nobody plays ETB creatures because they expect you to hate them out? If that's the case, I think you should at least ask your playgroup if they'd be interested in playing the type of Magic that you like to play, and if that doesn't pan out maybe look for people who want to play the same kind of Magic as you instead of trying to punish other people for doing things that they enjoy doing in their games of Magic.
I don't think the list will have enough creatures to use Peel from Reality without having to bounce Kefnet. However, I do find Aether Tradewinds playable.
I had considered Distortion Strike and Taigam's Strike, but if they are one of the 7 cards in hand then Kefnet won't be able to attack that turn. The same unfortunate problem also applies to Key to the City where the payoff is delayed.
I think you can activate Key to the City after attacks but before blocks. Though I don't think you really need to spend many card slots on making sure Kefnet goes unblocked, since he has flying and all. Also keep in mind that in multiplayer EDH, you'll always be on the draw and Kefnet won't cost you a card in hand, so you don't actually need to work too hard to keep 7 cards in hand.
It's in the OP, hover over "Discard Outlets."
The trick doesn't actually work with Hope of Ghirapur, since after the first sacrifice, the game treats your recurred Hope of Ghirapur as a new game object that has not dealt combat damage to any player, which translates to you not being able to activate its ability because there are no valid targets for it. However, this would work with many cards that you don't have in the list like Bottle Gnomes (also arbitrary lifegain), Coretapper (more charge counters than you can shake a stick at), Lurebound Scarecrow (pick a permanent color you don't have), Phyrexian Dreadnought (lol), Thermal Navigator, or Ticking Gnomes (arbitrary damage).
My mind has just been blown.
The tokens would also require haste.
50% of the time this is basically Nev's Disk
25% of the time this is much worse than Nev's Disk.
I'd be inclined to play it in a deck that can break its symmetry or mitigate some of the variance of the coin flip, or in a deck that otherwise can't really answer certain permanent types. I think it also has a place as part of a Transmute Artifact/Reshape/Whir of Invention package as well, since it can be activated as soon as it is tutored out. Whirring for an instant speed hail Mary board wipe sounds like a lot of fun for the whole table. I'd play it in heavy artifact decks like Slobad, Goblin Tinkerer, Kurkesh, Onakke Ancient, or maybe even Arcum Dagsson, since those decks almost always play Darksteel Forge, Rings of Brighthearth, Voltaic Key, and Clock of Omens. It also has some niche uses with commanders that can animate lands.
What's your end goal here? Is it to win? If so, have you considered simply playing powerful creatures yourself instead? Is your goal to force some kind of metagame where nobody plays ETB creatures because they expect you to hate them out? If that's the case, I think you should at least ask your playgroup if they'd be interested in playing the type of Magic that you like to play, and if that doesn't pan out maybe look for people who want to play the same kind of Magic as you instead of trying to punish other people for doing things that they enjoy doing in their games of Magic.
I think you can activate Key to the City after attacks but before blocks. Though I don't think you really need to spend many card slots on making sure Kefnet goes unblocked, since he has flying and all. Also keep in mind that in multiplayer EDH, you'll always be on the draw and Kefnet won't cost you a card in hand, so you don't actually need to work too hard to keep 7 cards in hand.
You could also lean on just regular old card draw effects, especially ones that refill your hand to 7 like Day's Undoing, Diminishing Returns, Magus of the Jar, Memory Jar, Time Reversal, Time Spiral, and if your budget can handle it, Timetwister.
Time Warp effects also replace themselves during the draw step of your extra turns, too.
Casting cards from the top of your library is an option too.