Sol Ring

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Mowu, Loyal Companion

Vigilance, trample
If one or more +1/+1 counters would be put on Mowu, Loyal Companion, that many plus one +1/+1 counters are put on it instead.

Colossification

Enchant creature
When Colossification enters the battlefield, tap enchanted creature.
Enchanted creature gets +20/+20.

Plains

Kutzil, Malamet Exemplar

Your opponents can't cast spells during your turn.
Whenever one or more creatures you control each with power greater than its base power deals combat damage to a player, draw a card.

Savage Firecat

Trample
Savage Firecat enters the battlefield with seven +1/+1 counters on it.
Whenever you tap a land for mana, remove a +1/+1 counter from Savage Firecat.

Alpine Watchdog

Vigilance (Attacking doesn't cause this creature to tap.)

Junk

{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.

Scoria Cat

Scoria Cat gets +3/+3 as long as you control no untapped lands.

Mountain

Zodiac Dog

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)

Pack Leader

Other Dogs you control get +1/+1.
Whenever Pack Leader attacks, prevent all combat damage that would be dealt this turn to Dogs you control.

Regal Caracal

Other Cats you control get +1/+1 and have lifelink.
When Regal Caracal enters the battlefield, create two 1/1 white Cat creature tokens with lifelink.

Arcane Signet

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

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Dogmeat, Ever Loyal

When Dogmeat enters the battlefield, mill five cards, then return an Aura or Equipment card from your graveyard to your hand.
Whenever a creature you control that's enchanted or equipped attacks, create a Junk token. (It's an artifact with "{T}, Sacrifice this artifact: Exile the top card of your library. You may play that card this turn. Activate only as a sorcery.")

Rin and Seri, Inseparable

Whenever you cast a Dog spell, create a 1/1 green Cat creature token.
Whenever you cast a Cat spell, create a 1/1 white Dog creature token.
{R}{G}{W}, {T}: Rin and Seri, Inseparable deals damage to any target equal to the number of Dogs you control. You gain life equal to the number of Cats you control.

Command Tower

Tyrranax Rex

This spell can't be countered.
Trample, ward {4}, haste
Toxic 4 (Players dealt combat damage by this creature also get four poison counters.)