Here is the full list of all 24 Idle Hero TD achievements.
Reach wave 250.
Reach wave 1000.
Reach wave 5000.
Reach battlepass level 10.
Reach battlepass level 35.
Reach battlepass level 50.
Unlock 15 heroes.
Unlock 50 heroes.
Unlock 100 heroes.
Reach rank 15 on any hero.
Reach 500 total ranks from all heroes combined.
Reach rank 50 on 25 different heroes.
Achieve 10 active synergies at once.
Achieve 20 active synergies at once.
Achieve 25 active synergies at once.
Obtain 100k kills with Melee heroes.
Obtain 500k kills with Range heroes.
Obtain 2.5m kills with Range heroes.
Kill 250k enemies.
Kill 1m enemies.
Kill 10m enemies.
Kill 25 Training Dummy bosses.
Kill 250 Ancient Shadow bosses.
Kill 750 Exotic Alien bosses.