Um...wood is good so long as it's not pressuretreated, and if it's au natural, you should bake it fora bitto clear out all the bugs and such. Others will be able to let you knowmore...
Commercial chew toys are usualy fun and safe, but different buns willhave different preferences, so you may need to do a littleexperimenting As far as treats go, those should be few andfar between, because they are high in sugar and other things that arenot so good for bunnies.