Here is the full list of all 25 Diablo IV achievements.
Kill 666 Snakes or Spiders.
Kill 666 Bandits, Cultists, or Knights.
Complete the campaign.
Kill 666 Ghosts, Skeletons, or Zombies.
Summon 100 Skeleton Mages or Warriors as a Necromancer.
Kill 666 Drowned, Vampires, or Werewolves.
Kill 666 Demons, Fallen, or Goatmen.
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 50 enemies in Werebear form and 50 enemies in Werewolf form as a Druid.
Explore all of Estuar.
Collect 1000 Aberrant Cinder in Helltide zones.
Reach Level 50 with any character.
Reach Level 50 with a Hardcore character.
Reach Level 100 with any character.
Complete a Sacred and Ancestral Nightmare Dungeon.
Upgrade your Healing Potion to max tier.
Get 5 PvP kills.
Kill 50 enemies in melee range and 50 enemies out of melee range as a Rogue.
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.
Kill any World Boss.