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