Arcane Signet

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

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.

Spirited Companion

When Spirited Companion enters, draw a card.

K-9, Mark I

Negative — As long as K-9, Mark I is untapped, other legendary creatures you control have ward {1}.
Affirmative — {1}{U}, {T}: Target legendary creature can't be blocked this turn.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Yoshimaru, Ever Faithful

Whenever another legendary permanent you control enters, put a +1/+1 counter on Yoshimaru, Ever Faithful.
Partner (You can have two commanders if both have partner.)

Sophia, Dogged Detective

When Sophia, Dogged Detective enters, create Tiny, a legendary 2/2 green Dog Detective creature token with trample.
{1}, Sacrifice an artifact token: Put a +1/+1 counter on each Dog you control.
Whenever a Dog you control deals combat damage to a player, create a Food token, then investigate.

Command Tower

Floodhound

{3}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Greater Tanuki

Trample
Channel — {2}{G}, Discard Greater Tanuki: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Sol Ring

Ainok Bond-Kin

Outlast {1}{W} ({1}{W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has first strike.

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.