A bunch of cards relating to the theme of exiling. No attempts have been made at balance or good naming.
Metaphysical Retaliator {4}
Artifact
Whenever a card you own is exiled, add a charge counter to {this}.
{2}, {T}, remove three charge counters from {this}: Exile target permanent.
Angel of Return {4}{W}{W}
Creature - Angel
Flying
Sacrifice {this}: Return target creature card that entered your graveyard from the battlefield this turn to the battlefield.
{2}{W}, exile {this} from your graveyard: Return target creature card that entered your graveyard from the battlefield this turn to the battlefield.
5/5
Blame Stick {1}
Artifact
{1}, exile {this}: The next time target permanent you own would be exiled this turn, instead it isn't.
Unreality Chain {4}
Artifact - Equipment
Fading 3
Whenever equipped creature blocks or is blocked by another creature, exile both creatures until {this} leaves the battlefield.
Equip {2}
Doppel Prison {1}{W}{U}
Enchantment - Aura
Enchant Creature You Don't Control
Fading 3
{W}{U}: Exile enchanted creature until {this} leaves the battlefield. {This} becomes a copy of that creature, becomes an enchantment in addition to its other card types, and gains Fading. When {this} leaves the battlefield, return it to the battlefield attached to enchanted creature.
Mome
Note: Mome is a supertype. It has no game rules unto itself.
Note: Mome is a joke. You'll notice that everything Mome requires another Mome to already exist before it can come into play. The Mome-related spells are less stringent, but that's also because they never put anything into play.
Note: I always imagine mome as something light and fluffy. Your interpretation may vary.
Summon Mome {U}
Sorcery
As an additional cost to cast Summon Mome, sacrifice a Mome permanent.
Search your library for up to two Mome cards, reveal them, and put them into your hand. Then, shuffle your library.
Mome Elemental {2}{U}{U}
Mome Creature - Elemental
Absorb 1
Flying
Hexproof
If Mome Elemental would enter the battlefield, you may sacrifice a Mome permanent. If you don't, exile it instead.
5/5
Mome Lord {4}{U}{U}{U}
Legendary Mome Creature - Elemental
Absorb 3
Hexproof
Trample
If Mome Lord would enter the battlefield, you may sacrifice three Mome permanents. If you don't, exile it instead.
When Mome Lord enters the battlefield, put two Mome Mote tokens into play. (Mome Motes are Mome Enchantment tokens.)
At the beginning of your upkeep, you may sacrifice a Mome permanent. If you do, put two Mome Mote tokens into play.
When Mome Lord dies, you may return it to the battlefield.
7/7
Infusion of Mome {2}{U}
Mome Enchantment - Aura
Enchant Creature
If Infusion of Mome would enter the battlefield, you may sacrifice a Mome permanent. If you don't, exile it instead.
Enchanted creature has Absorb 1 and Hexproof.
Enchanted creature gets +2/+2.
Enchanted creature is Mome in addition to its other supertypes.
Detonate Mome {1}{R}
Sorcery
As an additional cost to cast Detonate Mome, sacrifice a Mome permanent.
Detonate Mome deals X damage to each non-Mome creature, where X is equal to the sacrificed permanent's converted mana cost.