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