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