Here is the full list of all 43 Diablo III: Reaper of Souls - there are Ultimate Evil Edition achievements worth 1,000 gamerscore.
Kill the Butcher.
Use a merchant to repair an item.
Kill the Skeleton King.
Pick up 500,000 gold.
Recruit the Templar, Scoundrel, and Enchantress.
Equip all Inventory slots with Legendary items that have a minimum required level of 70 or higher.
Socket a gem in an item.
Complete 5 Bounties.
Complete 500 Bounties.
Kill 500 Monsters while in Nephalem Rifts.
Finish a Nephalem Rift within 15 Minutes.
Complete all quests in Act I.
Kill Maghda.
Kill Zoltun Kulle.
Kill Belial.
Complete all quests in Act II.
Kill Ghom.
Kill the Siegebreaker Assault Beast.
Kill Azmodan.
Complete all quests in Act III.
Kill Diablo.
Complete all quests in Act IV.
Kill Urzael.
Kill Adria.
Kill Malthael.
Complete all quests in Act V.
Reach level 70 in Hardcore mode.
Kill Diablo in Hardcore mode.
Kill Malthael in Hardcore mode.
Reach level 70.
Reach level 70 with 6 different classes.
Kill 500 elite (champion, rare, or unique) enemies.
Kill 100 Treasure Goblins.
Get a destruction callout for breaking 50 objects.
Craft 5 items.
Craft 100 items.
Raise the Blacksmith to level 12.
Raise the Jeweler to level 12.
Raise the Mystic to level 12.
Enchant all your equipment slots.
Replace a property with Enchanting.
Acquire the Mystic.
Combine gems.