There are 28 achievements tracked for xNetHack in the Junethack tournament.
ascended
entered Astral Plane
entered Elemental Planes
obtained the Amulet of Yendor
performed the Invocation Ritual
obtained the Book of the Dead
obtained the Bell of Opening
obtained the Candelabrum of Invocation
entered Gehennom
defeated Medusa
obtained the luckstone from the Mines
obtained the Sokoban Prize
escaped in celestial disgrace
killed by Moloch's indifference
read a Discworld novel
consulted the Oracle
entered a shop
entered a temple
entered Sokoban
entered the Gnomish Mines
entered Mine Town
entered the Big Room
ascended without scaring any monsters
ascended without having a pet
ascended without touching an artifact
ascended while hallucinating permanently
ascended being permanently deaf
completed the revised Archeologist quest