Ok my idea is adding bear traps, they can be made from any metal besides tin and copper and will be used to trap any animal. They should be visible so players wont run into them unless they are really stupid. The reason bear traps wont over powered is because there is a low chance for animals to walk into them since its just one tile out of a billion. they can be there just for an easy catch every once in a while. So they cant be used to siege other players i suggest making them deactivatable (<-- not a real word). So whats the point of having bear traps if people can just deactivate and steal them? well thats simple, not everyone is a butt hole.
Additional featuresThey cant kill players but deal damage and cripples them making them crawl for a while
Making a bear trap requires metal working, hunting and, animal husbandry
The better the metal and the higher your smithing/strength the more damage towards people and animals
This may make it easier to kill trolls but if you don't want that just make trolls immune

Make them visible enough for players to see if they are paying attention
*edit I never said it was just for bears