Here is the full list of all 69 Nevergrind Online achievements.
Hit level 50 with a Warrior
Hit level 50 with a Monk
Hit level 50 with a Rogue
Hit level 50 with a Crusader
Hit level 50 with a Shadow Knight
Hit level 50 with a Ranger
Hit level 50 with a Bard
Hit level 50 with a Druid
Hit level 50 with a Cleric
Hit level 50 with a Shaman
Hit level 50 with a Warlock
Hit level 50 with a Enchanter
Hit level 50 with a Templar
Hit level 50 with a Wizard
Trained a skill to level 7
Found a magical item
Found a rare item
Found a set item
Found a unique item
Completed a normal mission
Completed a heroic mission
Vanquished Lord Szarthax
Completed a mission in Salubrin Haven
Completed a mission in Tendolin Passage
Completed a mission in Greenthorn Cavern
Completed a mission in Lanfeld Refuge
Completed a mission in Bastille Citadel
Completed a mission in Kordata Cove
Completed a mission in Sylong Sanctuary
Completed a mission in Thule Crypt
Completed a mission in Temple of Prenssor
Completed a mission in Fahlnir Citadel
Completed a mission in Anuran Ruins
Completed a mission in Galeblast Fortress
Completed a mission in Ashenflow Peak
Receive +3 to a buff from a curio
Found at least four items in a treasure chest
Find more than 500 gold in a treasure chest
Trained your first skill
Completed a mission in Riven Grotto
Hit level 95 with a Warrior
Hit level 95 with a Monk
Hit level 95 with a Rogue
Hit level 95 with a Crusader
Hit level 95 with a Shadow Knight
Hit level 95 with a Ranger
Hit level 95 with a Bard
Hit level 95 with a Druid
Hit level 95 with a Cleric
Hit level 95 with a Shaman
Hit level 95 with a Warlock
Hit level 95 with an Enchanter
Hit level 95 with a Templar
Hit level 95 with a Wizard
Hit level 90 with a Warrior in Hardcore
Hit level 90 with a Monk in Hardcore
Hit level 90 with a Rogue in Hardcore
Hit level 90 with a Crusader in Hardcore
Hit level 90 with a Shadow Knight in Hardcore
Hit level 90 with a Ranger in Hardcore
Hit level 90 with a Bard in Hardcore
Hit level 90 with a Druid in Hardcore
Hit level 90 with a Cleric in Hardcore
Hit level 90 with a Shaman in Hardcore
Hit level 90 with a Warlock in Hardcore
Hit level 90 with an Enchanter in Hardcore
Hit level 90 with a Templar in Hardcore
Hit level 90 with a Wizard in Hardcore
Found a legendary item