Mister Cheddar, Cheese Sliver{4}{B}Legendary Creature — Rat SliverRats and Slivers you control are Rat Slivers in addition to their other types and have ratmanship. (They can't be blocked except by Cats, Rats, or other creatures with ratmanship.)
As long as Mister Cheddar is your commander, Sliver cards in your deck have "Your deck may contain any number of this card." 5/5 Catch-Up Mechanic{4}{W}Creature — Human ArtificerWhen this creature enters, choose one. If an opponent has at least 5 more life than you, choose any number instead—
• Put two +1/+1 counters on another target creature or Vehicle.
• Return target artifact card from your graveyard to your hand.
• Look at the top five cards of your library. Reveal an artifact card from among them and put it into your hand. Put the rest on the bottom in a random order. 4/4 Tarkiran Towelsbane{5}{R}{W}Legendary Creature — Shark RebelWhen Tarkiran enters, create five 1/1 red Human Rebel creature tokens.
Whenever one or more Rebels you control deal combat damage to a player, you gain 2 life. 2/2 X, Mystery Racer{3}{U}{B}Legendary Creature — Human SpyWhen X enters, you may put it into target opponent's hand. If you do, as long as it remains in their hand, that player can't cast X and they play with their hand revealed.
During your turn while X is in an opponent's hand, you may activate abilities of nonland permanents opponents control. If you activate the crew or saddle ability of a permanent this way, gain control of it until end of turn. Untap it. It gains haste until end of turn. 5/5 The Good Time Sleuth{3}{W}{B}Legendary Creature — Human?When The Good Time Sleuth enters, exile the top card of your library and each nontoken creature you control in a face-down pile, shuffle that pile, then manifest those cards. Then create a Blood token for each face-down creature you control. Those creature gain "Sacrifice a Blood: Turn this creature face up." Secretly choose one of them. As that creature is turned face up, reveal the choice and it becomes a 5/5 black Demon. 3/3