The answer is not a simple one as it varies from set to set, but one of the most important duties is something that I do every set
This little guy traded its ground-type origins for an icy shell, and it's just adorable yet tough
Arcbound Ravager Brokkos, Apex of Forever Brokkos, Apex of Forever Craterhoof Behemoth Cultivator Colossus Deathmist Raptor Elder Gargaroth Felidar Sovereign Gahiji, Honored One Godsire Hauntwoods Shrieker Highcliff Felidar Hydroid Krasis Illuna, Apex of Wishes Illuna, Apex of Wishes Loot, the Key to Everything Loot, the Pathfinder Marath, Will of the Wild Nethroi, Apex of Death Nethroi, Apex of Death Nullhide Ferox Otrimi, the Ever-Playful Protean Hulk Questing Beast Rampaging Baloths Slippery Bogle Tayam, Luminous Enigma Uril, the Miststalker Woodland Bellower Yannik, Scavenging Sentinel
Currently, slotting the combo pieces into Gruul Ponza seems like the best bet
I found the first two to be the most challenging in these pieces