Rootcoil Creeper | Creature | Plant Horror | {T}: Add one mana of any color.
{T}: Add two mana of any one color. Spend this mana only to cast spells from your graveyard.
{G}{U}, {T}, Exile Rootcoil Creeper: Return target card with flashback you own from exile to your hand. | Iris Compiet
4.0 LSV
Kessig Naturalist | Creature | Human Werewolf | Whenever Kessig Naturalist attacks, add {R} or {G}. Until end of turn, you don't lose this mana as steps and phases end.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.) | Johan Grenier
3.5 LSV