I have my favorite fusion combo, my "god slayer" if you will. It's an aeroboros/miasmodeus fusion with broadcast, ritual, dodge, and roll again as support on aeroboros, then roll again and random starter on miasmodeus. Also with chemical imbalance leading to trick. And then between them I have spit on both just in case I run out of action points, and then zephyr, thunder blast, damage roll, coal story, and pustule bomb, so that I can hit most things for super effective and get as many free tricks off as possible, and then since they're both special attackers, I also have raised arms. So in an ideal turn I get 5*/6 moves off, buffing myself, landing a super effective hit or 2, proccing chemical imbalance and debilitating the enemy with trick. Or if fighting a boss that I know will be immune to statuses I just swap out trick for treat beforehand to even further buff myself. Also helps that coal story and pustule bomb guarantee burn and poison respectively, and thunder blast lets me turn earth types into glass types with 1 stack of resonance all in one move

*=5 moves when fused, 6 when not