MTG Salvation

Velris, Simgari Swarmseer GUB
Legendary Creature - Elf Shaman
Inspired - Whenever ~ becomes untapped, you may sacrifice a creature. If you do, scry 1, then draw a card.
Discard a card: Put two 1/1 green and black Plant Mutant creature tokens onto the battlefield.
When Velris brought the two guilds together, failed Simic creations found new purpose as fodder for the Golgari swarm.
(2/2)

Next: Try mixing another two Ravnica guilds.

This creates interesting synergy with haste and flickering. Would make for an interesting EDH build with a bunch of hasters with enter the battlefield effects. I might make the flickering cost 1WU just to make repeated ETB abuse just a little more costly.

Next:

Diminish Hopes 1BB
Sorcery
Put X -1/-1 counters on target creature, where X is that creature's toughness minus 1.

Yeah... This is pretty much at least a hasted 6/2 with no downside and tons of upsides with double-strike and late game growth. Pretty terrifying.

Last Thoughts 1UB
Enchantment
Whenever you lose life outside of combat, scry 1.

Wild Hallucinations 1GU
Enchantment
When ~ enters the battlefield, choose a creature type.
Creatures are the chosen type in addition to their other types.
At the beginning of your upkeep, sacrifice ~ unless you pay 1GU

Inixet, Phantom Tinkerer 2UR
Legendary Creature - Spirit Artificer
Imprint - When ~ enters the battlefield, you may exile target noncreature artifact.
Champion a non-artifact creature
~ is a copy of the championed creature with all activated abilities of the exiled artifact.
(0/0)

Next: A commander that really shines when an opponent is close to winning.

Feels pretty broken with any kind of sacrifice outlets. It has a small body, but the hexproof prevents anything short of a board wipe from doing the job so it's not much of a downside. I would either bump up the mana cost, at least.

Here's an odd one that needs tweaking, most likely:

Mentino, Trader of Enigmas RWU
Planeswalker - Mentino
+1: Target player gains control of target permanent you control. Each other player puts a 0/1 white Goat creature token onto the battlefield.
-1: Untap up to one target noncreature artifact and gain control of it until end of turn. Target opponent gains 2 life.
-5: You get an emblem with "At the beginning of your upkeep, Goat creature tokens you control become copies of target noncreature artifact."
(2)

I don't see Heliod putting up with that for long. Too spiteful.

Heliod, the Setting Sun 2WW
Legendary Creature - Human Soldier
Vigilance
Whenever ~ deals combat damage to an opponent, you may exile it and target creature in a graveyard. If you do, return those creatures to the battlefield under their owner's control at the beginning of your next upkeep.
"Cast me aside, will they? I will show them the savior I am."
(3/3)

Next: I want to see Elspeth imagined as a Returned.

Hmm. Interesting take on the idea. Both this one and the Passive Duelist above are getting really close to what I was planning one take on the ability. Putting +1/+1 counters on a noncreature is counter intuitive for some people, just like Rampaging Ravine and similar cards, so this would need to be at least uncommon. It's also an interesting idea that it completely loses the Resolute ability as well, so you're stuck with however many counters you choose.

As far as waiting being "not fun," it's supposed to be entirely optional. You aren't necessarily encouraged to wait at all times, you just get a small benefit during the times when attacking is not a good idea. For instance, the Patient Soldier above is at least a bear, if you need to go agro.

Next: This guy.

Belwyr, Captain of the Walls 2W
Legendary Creature - Human Soldier
Defender
Creatures you control have patience. (At the beginning of your end step, if you did not attack this turn, put a +1/+1 counter on this creature.)
As long as ~ has five or more +1/+1 counters on it, creatures you control lose defender and can't have or gain defender.
(0/4)

Sort of a Slumbering Dragon crossed with the Archetype ability. I still like the name "Patience" for the ability, though. I plan for it to be a white/blue keyword splashed into black for the flavor of waiting and plotting for the exact moment to strike. Still need to figure out how, exactly, but It would also be amusing if "losing patience" had a mechanical implication.

I don't really know how I feel about Bestow creatures that aren't symmetrical. The effect is potentially really powerful, but once it pops off it's vanilla. I really wish there was a way to give the enchantment creature the same ability without having to make it really wordy. At the very least, the cost seems about right for the effect, comparable to Soul's Fire.

Next: Trying out a small example for a new ability before trying it out on more complex creatures.

Passive Soldier 1W
Creature - Human Soldier
Patience (At the beginning of your end step, if you did not attack this turn, put a +1/+1 counter on this creature.)
(1/1)

Polukranos is usurped by an octopus! Need an alternative option to Lorthos for theme decks anyway.

Velobracktis, Sea of Arms 2GGUUBB
Legendary Creature - Octopus
7GUB: Monstrosity 0
When ~ becomes monstrous, the controllers of up to eight target creatures each sacrifice those creatures. Put X +1/+1 counters on ~, where X is the total toughness of the sacrificed creatures. ~ gains nonbasic landwalk.
(8/8)

Next: Who will rise to fight this monster?

Quote from tenangrychickens »

Hell no. This is insane - Red gets this ability at 6 mana for a sorcery, and that's only from the hand. This is stupid good.

That's why it specifically does not give you control of the spell. The opponent has to cast it, but they still control it, choose all targets, and get the effect of anything that says "you". For instance, you can search out a Time Walk all you want, but they're the one that's going to take the extra turn. Granted, it needs some limiters to prevent someone from searching out stuff like All is Dust.

For Sanity Siphon, non-aura enchantments can't really attach to anything. You'd need some really wordy ability that turns it into an aura, like some sort of non-creature version of Bestow. The "increase effect by one" clause also doesn't really work, because there's no way to gauge a card's effect numerically. I don't know if you can really work everything you want it to do into one streamlined card.

EDIT:

Unquenchable Blade sounds really terrifying. Like, you have a tiny bit of life gain, and then swing with a creature that has anywhere from +10 to +40 depending on the format. I feel like there's an issue somewhere with the value of X being put in the wrong place. I would avoid the issue and reword everything to "+1/+1 for each charge counter" and "Pay 1 life for each charge counter."

Next: Forcing something out of it's ordinary color pie?

Illuminated Wraith WWWW
Creature - Horror
Shroud
At the beginning of your upkeep, put a -1/-1 counter on ~.
Not all beasts can last in this light.
(6/6)

I get that self-sacrifice for the sake of others is white's territory, but I still don't like seeing this mechanic in mono-white. A little bit of reanimation in white is seen here and there, but sac outlets like this are even more sketchy. It goes with Athreos, so you might as well make it WB.

Next: Unorthodox tutor?

Force Hand UU
Instant
Search target opponent's library for an instant or sorcery spell and reveal it. That player casts the revealed spell without paying its mana cost if able.
I appreciate you coming prepared.

Great for when you really need a board wipe, or when the only valid targets of a spell would benefit you. Is such a low cost fair if you don't get to control the spell?

Barrosh, Siege Lord 5WW
Legendary Creature - Wall Praetor
Defender
Creatures you control have first strike.
Creatures your opponents control have defender.
(4/8)

Next: Zombie Phelddagrif

The wording feels really awkward, but it's an interesting idea. The idea is to remove your library and be unkillable.

The last ability is a problem, though, because it means the whole enchantment doesn't really do anything useful. If your opponents can destroy Emptiness at any time, it will never save you from losing the game. When you run out of cards in your library, your opponent would just sac their graveyard and permanents right before your draw step and you lose. The whole hexproof "can't lose" part never really comes into play.

Next:

Blissful Ignorance 1WU
Enchantment
At the beginning of your upkeep, you may put a null counter on target enchantment.
Enchantments with null counters are colorless, noncreature enchantments with no abilities.
You lack imagination. Good.