Green has lots of stuff like Noxious Revival and Bala Ged Recovery  ^Flip that can get your Shivan out of the graveyard, and as I've pointed out there are some White cards that let you reanimate it if it's dead (or iirc take it out of exile if someone exiles it, with Pull from Eternity).

I looked up to see if there were some more decent White reanimator effects, there is Karmic Guide (also provides a blocker), Defy Death (pretty bad), Invoke Justice (better but how do you cast this!), Enduring Renewal (really, really janky), Second Sunrise (very situational), Angelic Renewal (seems good), Breath of Life (solid), Cleric Class (mana hungry/low synergy with deck), Elspeth Conquers Death (maybe?), False Defeat ($$$), Late to Dinner (good), Marshal's Anthem (mana!), Miraculous Recovery (good), Resurrection (fine), Reya Dawnbringer (so much mana). There is probably a few more, but here is a starting point, I think with your Commander the Sorcery ones make a lot of sense, but a creature that can repeatedly reanimate Shivan seem like better fits but I don't know how annoying it will be to Egg into them.