Diminished Returner

Enlist Whenever Benalish Knight-Counselor enlists a creature, you get a one-time boon with "When you cast a creature spell, that creature enters with a +1/+1 counter on it."

When Priest of Possibility enters, look at the top seven cards of your library. If a card among them has flying, Priest of Possibility perpetually gains flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, protection, reach, trample, and vigilance. Then shuffle.

Kicker 1U When Pull of the Mist Moon enters, exile target nonland permanent an opponent controls until Pull of the Mist Moon leaves the battlefield. When Pull of the Mist Moon enters, if it was kicked, choose a nonland permanent card in your hand. It perpetually gains "When this permanent enters, exile target nonland permanent an opponent controls until this permanent leaves the battlefield."

Flying When Oracle of the Alpha enters the battlefield, conjure the Power Nine into your library, then shuffle. Whenever Oracle of the Alpha attacks, scry 1.

Flying Domain — When Skywriter Djinn enters, conjure a random card from Skywriter Djinn's spellbook into your hand. Then if you have fewer cards in hand than the number of basic land types among lands you control, repeat this process.

When Trove Mage enters, seek an artifact card from among the top ten cards of your library, then shuffle.

Kicker 1B Return target nontoken, nonland permanent to its owner's hand. If this spell was kicked, conjure a duplicate of that card into your hand. It perpetually gains "You may spend mana as though it were mana of any color to cast this spell."

Kicker 1R Flying Whenever you draw a Dragon card, it perpetually gets +1/+1. When Darigaaz's Whelp enters, if it was kicked, seek a Dragon card. Darigaaz's Whelp and that Dragon card each perpetually get +1/+1.