The Gosei Great Gattai sequence in Epic 2. What pushed the scene most is NoB singing its Leitmotif in the background.
The Goseigers defeating Dereputa in Epic 12, first each tribe gives him a good beating, followed by Gosei Buster's Gosei Dynamic finisher. And to top it off, they combine Gosei Great, the Seaick, Landick, and Skick Brothers, and Datas Hyper to form Hyper Gosei Great taking him down.
Their final battle against Mons Drake in Epic 15 when they blast Mons Drake into his ship.
Alata and Dereputa's final battle in Epic 16.
Epic 17; pretty much the latter part with Gosei Knight and Groundion's debut.
Epic 19 takes it further with the premiere appearance of Gosei Ground.
The debut of the Super Goseigers in Epic 24 definitely counts.
Episode 27: Kinggon, one of the current Big Bads, attacks Agri while Agri's going through a Heroic B.S.O.D.. Once said BSOD is over, a pissed-off Agri Chou Tensou's into Super Gosei Black and then beats the crap out of Kinggon.
Two Words: Gosei Ultimate
Epic 47 - Hyde vs Brajira.
Alata gets a few as well, once in Epic 48 where he falcon punches GoseiKnight in an "I know you're in there somewhere" battle, and in 49 where, after getting the crap beat out of him by Brajira, ignores the idea of using his teammates power (ie sacrificing them to power himself up), runs at Brajira, gets tossed around some more while still giving a rousing speech. This climaxes with him knocking a shot from Brajira away with HIS BARE HANDS.
As expected with most teamup movies, Goseiger vs Shinkenger is a wealth of awesome moments. Super Change cards for all the Shinkengers, Ground Hyper Gosei Great, and nicely done henshin and role call sequence to boot, never mind the Gokaiger'sEarly-Bird Cameo.
Epic 50: Alata, the Red that tends to get picked on for not being Rated M for Manly like the ones before him, kills Brajira, the Big Bad.