You want heroes with good synergy for the different rules… I have one of every 3* hero maxed (except for Nodri… don’t have him yet )
Obviously heroes who make buffs & do so quickly are good here. Gunnar / Kailani are the exception as they work well at tank.
Dispellers are good here as they remove the enemy bonuses (e.g. Tyrum, Belith, Mnesseus etc…)
Heroes here who have good damage output & quickly are good. So snipers etc… Also Kavisr ROCKS in this format as the minions he makes is like a pseudo heal… creates a meat shield.
Cleansers are REALLY good here as they remove some of the negative effects coming from the enemy “slow” heroes (e.g. Costume Tyrum & Gill-Ra)
This is where some of the slower heroes shine. So heroes like Gunnar, Ulmer, Oberon, Jahangir, Arman etc… The snipers still help & some of the good healers are handy too (e.g. costume hawkmoon) when they have secondary effects.
Also helps with some of the “annoying” heroes who become nightmares when sped up (e.g. Bauchan or Shrubbear)
Some heroes just are really good general utility heroes who help to drop in on teams. Ones like Costume Hawkmoon, Brienne/Costume Brienne, Kavsir.
Mana controllers also fit into this bracket. Heroes like Ei-Dunn & Bauchan & Chochin & Azar (particularly her costume) & Pixie.