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