The usual suspects. (They've committed arson.)

[Bwixie]

Currently have a team of Golem, Dark Magmoth, and Light Lion.
Tons of burn debuffs and buffs, tons of shielding and damage.
I have others that take advantage of burns and debuffs for keeper battles but these are what I use for everything else and are the first 3 out.

Lion stacks buffs with crits, Magmoth does high damage and builds burns and charge stacks from those. Golem is probably the most replaceable, but I wanted to be able to cure our debuffs and have even more multi-burn to destroy enemy buffs, plus can use the shielding generated by Magmoth's attacks in a shield burst for occasional big damage finishes.

Very fun team, can usually KO a monster every other turn. Achieved 5 stars on so many champions, even ones that resist fire or debuffs thanks to all the stacking. Once had to revive Magmoth and still got 5 stars, it's that crazy.