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