Here is the full list of all 20 Prehistoric Tales achievements.
For eliminating 250 dinosaurs.
For winning 20 battles.
For using 30 spells in battles.
For using 70 spells in battles.
For reaching level 25.
For rescuing the valley from the invasion of greenskins.
For 200 exchanges with traders.
For reaching level 15.
For winning 7 battles.
For building 40 constructions in your settlement.
For 70 exchanges with traders.
For making friends with a little greenskin.
For reaching level 10.
For starting trade relationships with neighboring tribes.
For building 15 constructions in your settlement.
For finding the arena of ancient battles.
For collecting 120 plants.
For winning 40 battles.
For finding 15 artifacts and rare items.
For finding 25 artifacts and rare items.