Pack Rat

Pack Rat's power and toughness are each equal to the number of Rats you control.
{2}{B}, Discard a card: Create a token that's a copy of this creature.

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Cecily, Haunted Mage

Your maximum hand size is eleven.
Whenever Cecily, Haunted Mage attacks, you draw a card and you lose 1 life. Then if you have eleven or more cards in your hand, you may cast an instant or sorcery spell from your hand without paying its mana cost.
Friends forever (You can have two commanders if both have friends forever.)

Forest

Seven Dwarves

This creature gets +1/+1 for each other creature named Seven Dwarves you control.
A deck can have up to seven cards named Seven Dwarves.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Rat Colony

This creature gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Elmar, Ulvenwald Informant

Haste
Whenever you cast your second spell each turn, untap target creature, then investigate. (Create a colorless Clue artifact token with "{2}, Sacrifice this artifact: Draw a card.")
Friends forever (You can have two commanders if both have friends forever.)

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Sol Ring

Relentless Rats

This creature gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.

Swamp

Persistent Petitioners

{1}, {T}: Target player mills a card. (They put the top card of their library into their graveyard.)
Tap four untapped Advisors you control: Target player mills twelve cards.
A deck can have any number of cards named Persistent Petitioners.