Conclave Vengeance
Instant (U)
Untap all creatures you control. Put a +1/+1 counter on each of those creatures.

Vampiric Plans -
Sorcery
Search your library for two cards. Shuffle your library. Put one of those cards into your library second from the top, then put the other on top of your library.

Multi-Duress -
Sorcery
Target opponent reveals their hand and discards all noncreature, nonland cards.

So is there one card between the two?
If not, could read "Search your library for two cards. Shuffle your library, then put those cards on top of it in any order"

There is one between the two, because you follow the instructions in order. It’s a combination of Long-Term Plans and Vampiric Tutor, but I don’t do Vampiric first and then say “third from the top” because that makes you lift two cards instead of one

Nourishing Nimbus
Enchantment - Aura
Enchant permanent
Whenever enchanted permanent deals damage, you gain twice that much life.
Discard an enchantment: Until end of turn, you may cast this card from your graveyard.

Originally just Spirit link x2 life, but I figured that would be too easy.

Spirit Bond
Enchantment - Aura
Enchant creature
Whenever enchanted creature deals damage, you gain twice that much life.

Imperial Assassin

Creature -- Human Assassin
2/2
: Destroy target creature.

Sanctum's Protection

Enchantment
Whenever a creature attacks you or a planeswalker you control, you gain 1 life.

Decree of Loss

Sorcery
Target player discards two cards and sacrifices a creature.

Enchanted Bogle
Creature — Beast
Play with the top card of your library revealed.
You may play the top card of your library if it's an enchantment card.
2/3

Bloodletting
Sorcery (U)
Bloodletting deals 1 damage to each creature. You gain that much life.
"Life causes so much agony. Let me help you with that."
—Sclenn, Wrexxilian surgeon

I feel like this should have been created by now, or at least some version of it, but I don't see it anywhere.

Ego -
Enchantment - Aura
Enchant creature
Enchanted creature's converted mana cost is 8.

Giant Leech

Creature -- Giant Leech
5/1
Lifelink
Menace

Invincible Blessing

Enchantment -- Aura
Enchant creature
Enchanted creature gets +3/+3 and has flying and indestructible.

Ascend to Sanctity

Instant
Target creature gets +1/+1 and gains flying and lifelink until end of turn.

Stampede Shaman

Creature -- Centaur Shaman
3/3
When Stampede Shaman enters the battlefield, target creature gains trample until end of turn.

Giant Leech really shouldn't have the giant type. Otherwise I approve.

Settler Druid

Creature -- Elf Druid
1/1
When Settler Druid enters the battlefield, search your library for a basic land card and put it onto the battlefield tapped. Then shuffle your library.
T: Add G.

That’s an old Pegaweb staple

Puts Farhaven Elf to shame, though.

Restoration Vines

Creature -- Plant Wall
0/4
Defender
When Restoration Vines enters the battlefield, you gain 4 life.

Yeah when I saw this my thought was, "Of course it hasn't been printed! It's too powerful!"

Could cost 1 more if needed.

Whip of the Deathless

Instant
Target creature gains deathtouch and indestructible until end of turn.

Leech's Bite

Instant
Target creature gets +1/+0 and gains lifelink and deathtouch until end of turn.

Hand of the Obzedat

Creature -- Human Assassin
2/2
When Hand of the Obzedat enters the battlefield, exile target creature an opponent controls.

Debt Due

Sorcery
Return target creature or planeswalker card from your graveyard to the battlefield.

Rock Hurl
Instant
Rock Hurl deals 3 damage to target creature.