Here is the full list of all 31 Idle Clans achievements.
Receive a boss key
Defeat a boss
Steal from the royal clan
Plunder a small, helpless village
Perform a leaderboard search
Eat a burger in battle
Equip diamond jewellery
The true test for any respectable chef... Make a pizza.
Prepare a special dish
Grow some watermelons
Reach max level in a skill
Reach level 100 in a skill
Create a godlike item
Battle a monster with an Outstanding weapon
Join a minigame
Purchase the most glamorous property available
Defeat a dragon
Purchase your first property. It's nothing to brag to your parents about, but it's a start.
Send an item to your clan's vault
Enchant an item
Create silver jewellery
List an item for sale
Purchase an upgrade
Achieved upon reaching your first million
Refine an item
Your first level up
Join a clan
Complete the tutorial
Create a clan
Reach a billion gold
Smith a piece of Astronomical armour