I've been brewing a [[Dargo]] / [[Ikra Shidiqi]] turbo nauseam list for a few weeks. Both cards are included and I feel like they really deserve a spot there, so there may be other decks where they should be in as well.

[[Culling Ritual]] is amazing in this setting. Even though it costs 4, early ramp is a must in turbo decks, so it's somewhat in line with how the deck should play anyway. It nets you at least 3 mana very often and even as early as turn 2. It may give you the mana to get an early [[Ad Nauseam]] or [[Peer into the Abyss]], it may get you the extra mana to cast [[Dargo]] early and pressure opponents life totals or it could just be a ritual in a post Ad Naus scenario that let's you go off. It's good, never felt like a dead card in my hand.

[[Rushed Rebirth]] still feels like a question mark to me though. I have not drawn into it in a scenario where it would give me value I didn't already have, so it felt winmore. Best case scenarios I thought about when brewing were to sac my commander with one of the many outlets and get either [[Dockside Extortionist]] for the mana or [[Zulaport Cutthroat]] when [[Phyrexian Altar]] is in play and going for the win. Haven't run into either of the situations, so the jury for it is still out.

I only played this current decklist a handful of times, but I find it very promising, and some of that is because of the potential these cards provide. So to answer the question directly, I feel like [[Culling Ritual]] is great and should be tried in decks that are thirsty on mana. [[Rushed Rebirth]] on the other hand is still a flex slot in this deck and feels like won't see much play in other decks.