I know, I know, probably never gonna happen, but it's fun to muse at. Here are a few suggestions:
Completionist
Acquire all Garden and Sanctuary keys from the Shadowlands.
Ding!
Level a character to 220/30/80.
Big Game Hunter
Defeat the Beast.
Knee Deep In Green Trouble
Defeat all the bosses from Sectors 13/28/35/42
The 12th Member
Defeat the Deranged Xan.
Eleet Hunter
Defeat Joo, Ownz, Morty, Stumpy, Ding and Powa.
Old School
Defeat Special Agent Lamb, Ljotur the Lunatic, The Pest, The One and the Obedience Enforcer.
The First of Many
Kill a Heckler.
A Dish Served Cold
Serve the head of the opposing general to your side's general.
Loremaster
Complete all Xan Civilization quests.
Hear Me Immortal One
Defeat Aztur the Immortal and Hezak the Immortal.
Keep em coming