Then you build a golem, you get bonus for items found while exploring. Does it give bonus for all kind of items or for the item it's made from?

Hello! 

Golems don't actually provide any exploring bonuses. They instead create resources that you harvest.  Basically you invest some materials into creating one, and they will in turn produce these materials until they are exhausted. It will only give materials for the item it is made from. You can have as many golems as you want, but only one of each material going at a time :) 

I hoped that helped some! 

Thank you :)