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