Some of the sorceries from the Face the Hydra deck might also work, as long as your group is willing to interpret the word Heads as creatures and think of the Chaos Deck as being the Hydra. For example, Unified Lunge would read, Unified Lunge deals X damage to each player, where X is the number of creatures on the battlefield. And Disorienting Glower could be interpreted as, Players cant cast spells until the next time a Chaos Deck card is played . Similarly, you could include some of the sorceries from the Battle the Horde deck by swapping out the word Minotaur for creature. Consuming Rage would then read, Whenever a creature attacks this turn, it gets +2/+0 until end of turn
No restrictions other than the banlist
Important cards to watch for in the Celestial Guardian set include Incineroar ex, Crabominable ex, and Solgaleo ex, along with Pom-Pom Style Oricorio
Both Jodah, the Unifier's triggered ability and the spell cast with that ability resolve before the spell that caused the ability to trigger, even if the original spell was countered in response