Here is the full list of all 25 Diablo IV achievements.
Complete the campaign.
Collect 1000 Aberrant Cinder in Helltide zones.
Upgrade your Healing Potion to max tier.
Kill any World Boss.
Kill 666 Bandits, Cultists, or Knights.
Kill 50 enemies while Berserking as a Barbarian.
Imprint 10 items at the Occultist with an Aspect from the Codex of Power.
Craft any Elixir and any Incense.
Kill 666 Demons, Fallen, or Goatmen.
Kill 666 Drowned, Vampires, or Werewolves.
Kill 50 enemies in Werebear form and 50 enemies in Werewolf form as a Druid.
Explore all of Estuar.
Kill 666 Ghosts, Skeletons, or Zombies.
Reach Level 50 with any character.
Reach Level 50 with a Hardcore character.
Reach Level 100 with any character.
Summon 100 Skeleton Mages or Warriors as a Necromancer.
Complete a Sacred and Ancestral Nightmare Dungeon.
Get 5 PvP kills.
Kill 50 enemies in melee range and 50 enemies out of melee range as a Rogue.
Kill 666 Snakes or Spiders.
Kill 100 enemies with Fire, Frost, or Lightning damage as a Sorcerer.
Kill the most challenging Echo of Lilith.
Upgrade a piece of Armor, Jewelry, and a Weapon.
Acquire 10 Caches of Chaos from the Tree of Whispers.