you may play exiled cards mtg that from exile The 51 Best Cast From Exile Cards in Magic Ranked Escape to the Wilds

I also wonder about splashing all the other colors

When I read the card, I initially thought that it had to be an instant or sorcery

It doesn't matter how your harmonize spell ended up in the graveyard the first time around

Now Im not going to keep repeating how +1/+1 counter synergies are everywhere, but what I really like otherwise about the abilities here is that you can trigger them on any turn once, so if you have an engine for life gain going and triggering on every turn with say Properous Innkeeper and Beledros Witherbloom (also in the deck), youll be sitting pretty on you next turn with possibly four 7/7 racoons