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