1.All Star Squadron issues 21-26 plus annual 2. America vs the Ultra Humanite.
2. Infinity Inc 1-4 Generations saga.
3.JSA (90s run) opening arc vs Mordru
4. Miller's arc in Daredevil wher he broke Matt, had kingpin discover his ID, ruinnis law service, kill his girlfriend etc etc.
5. Defender story around issue 100 where the Defenders fight Satan and Daimon goes against his father.
Close but not quites/Honorable mentions
Cosmic Odyssy
JLA/JSA/LOSH pre crisis cross over vs Mordru
Great Darkness Saga
Longbow Hunters (vertually any Green Arrow written by Grell)
Question Quarterly (hard to pick a specific arc)
Ostranders run on Spectre
The Alpha flight arc vs L'un
The Defendera arc where Eternity had split of aspects of himself to experience life.
Defenders arc where Devil Slayer went against the cult that trained him in mysicism.
Longshot mini series
Longshot saves the MU