All 21 Combos with Granite Witness

Yedora, Grave Gardener + Granite Witness + Skirk Alarmist + Atog

Other: Infinite LTB, Infinite sacrifice triggers, Infinite death triggers, Infinite green mana, Infinite landfall triggers, Infinitely large creature until end of turn

Activate Atog by sacrificing Granite Witness. When Granite Witness dies, Yedora triggers, returning Granite Witness from your graveyard to the battlefield face-down as a Forest land. Resolve the Atog ability, giving it +2/+2 until end of turn. Activate Granite Witness by tapping it, adding {G}. Activate Skirk Alarmist by tapping it, turning Granite Witness face-up. Granite Witness triggers, untapping Skirk Alarmist. Repeat.