Limited myself to one per game.
#10: Shadow Jago (Killer Instinct 2013)
#9: Golden Deer Final Boss/Map (Fire Emblem: Three Houses)
#8: Rebel Flagship (FTL)
#7: Jack Baker (Resident Evil 7)
#6: Index Guntyr (Dark Souls 3)
#5: Asura (Asura's Wrath)
#4: Prince Vorkken: Teio Form (Wonderful 101)
#3: Diggernaut (Metroid: Samus Returns)
#3: Grima (Fire Emblem: Awakening)
#2: Jetstream Sam (Metal Gear Rising)
#1: Final Boss (Devil May Cry 5)
That's what came to mind at least. Probably way more that I'm just not able to think of at the moment.