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 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 Winter's Demonmech{5}Artifact Creature — HorrorYou can't include this card in your deck if you're on Team Cloudspire.
Flying
Whenever this creature deals combat damage to a player, create a copy of one of the following, chosen at random: Early Winter, Plunge into Winter, Winterflame, Winter Sky, Winter's Grasp, or Winter's Intervention. You may cast the copy without paying its mana cost. 4/4 The Mysterious Sphere{5}Legendary ArtifactAdvertising — {T}: Exile the top card of your library. You gain 1 life.
Show — At the beginning of combat on your turn, if there are three or more cards exiled with The Mysterious Sphere, you may put them into your graveyard. If you do, create copies of each nonland card among them. You may cast the copies without paying their mana costs. If you cast a creature spell this way, it gains haste and "Sacrifice this creature at the beginning of your end step." Devoted Mardu{4}{W}Creature — Human WarriorVigilance
Mobilize X, where X is your devotion to Mardu. (Whenever you attack, create X tapped and attacking Mardudes (tapped and attacking 1/1 red Warrior creature tokens). Sacrifice them at the beginning of the next end step. I'm out of room. You remember what devotion does, right? Counts {R}, {W}, and {B}!) 5/3