Many things from PvE and some pvp and wvw, maybe:
-PvE
Complete story, including LW and xpacs
Map complete
All Raids, fractals, strike missions, dragon response missions, and dungeons done
All mastery levels and mounts unlocked
One legendary weapon, trinket, armour, and rune or sigil bound
30k or some other AP requirement?
PvP
Rank 60? 80?
WvW
Rank 1500? 2000?