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