Bill the Pony

When Bill the Pony enters, create two Food tokens. (They're artifacts with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Sacrifice a Food: Until end of turn, target creature you control assigns combat damage equal to its toughness rather than its power.

Bristly Bill, Spine Sower

Landfall — Whenever a land you control enters, put a +1/+1 counter on target creature.
{3}{G}{G}: Double the number of +1/+1 counters on each creature you control.

Bill Ferny, Bree Swindler

Whenever Bill Ferny, Bree Swindler becomes blocked, choose one —
• Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
• Target opponent gains control of target Horse you control. If they do, remove Bill Ferny from combat and create three Treasure tokens.

Bill Potts

Whenever you cast an instant or sorcery spell that targets only Bill Potts or activate an ability that targets only Bill Potts, copy that spell or ability. You may choose new targets for the copy. This ability triggers only once each turn.
Doctor's companion (You can have two commanders if the other is the Doctor.)