Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Reflection of Kiki-Jiki

{1}, {T}: Create a token that's a copy of another target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Fable of the Mirror-Breaker

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 2/2 red Goblin Shaman creature token with "Whenever this creature attacks, create a Treasure token."
II — You may discard up to two cards. If you do, draw that many cards.
III — Exile this Saga, then return it to the battlefield transformed under your control.

Fable of the Mirror-Breaker // Reflection of Kiki-Jiki

Goblin Matron

When Goblin Matron enters, you may search your library for a Goblin card, reveal that card, put it into your hand, then shuffle.

Dragon Fodder

Create two 1/1 red Goblin creature tokens.

Basalt Ravager

When Basalt Ravager enters, it deals X damage to any target, where X is the greatest number of creatures you control that have a creature type in common.

Krenko, Mob Boss

{T}: Create X 1/1 red Goblin creature tokens, where X is the number of Goblins you control.