Foundry Inspector

Artifact spells you cast cost {1} less to cast.

Enthusiastic Mechanaut

Flying
Artifact spells you cast cost {1} less to cast.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Ugin, Eye of the Storms

When you cast this spell, exile up to one target permanent that's one or more colors.
Whenever you cast a colorless spell, exile up to one target permanent that's one or more colors.
+2: You gain 3 life and draw a card.
0: Add {C}{C}{C}.
−11: Search your library for any number of colorless nonland cards, exile them, then shuffle. Until end of turn, you may cast those cards without paying their mana costs.

Elsha of the Infinite

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
You may look at the top card of your library any time.
You may cast noncreature spells from the top of your library. If you cast a spell this way, you may cast it as though it had flash.