Curiosity effects and Aether Tunnel effects are both welcome, as are removal auras like Amphibian Downpour
These decks have all the cards you need to immediately start playing
(If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.) Whenever one or more +1/+1 counters are put on this creature, it gains double strike until end of turn
Thada Adel, Acquisitor Thada Adel, Acquisitor is a dedicated Sol Ring thief against blue based decks in Commander
It offers win conditions (Ral, Storm Conduit), ramp (Storm-Kiln Artist), and card advantage (Archmage Emeritus)
In order to do this, almost every single creature in the deck has an enters-the-battlefield trigger that will generate small-to-medium-to-huge swings if theyre left unchecked