Best expansion/Large DLC ever.

[UnderwaterFunktown]

1. The Frozen Throne
2. Burning Crusade/Wrath of the Lich King
3. Witcher 3 expansions
4. Half-Life 2 Episode 1 & 2
5. Heart of the Swarm

Also a couple of great rereleases that are sort of like expansions - Persona 5 Royal and The Stanley Parable Ultra Deluxe.