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