On the desert side of the state there are wild horses! Actually becoming a problem as the population is about double what the land can really sustain.
https://www.onlyinyourstate.com/oregon/wild-horses-or/
If you go to the coast there is of course Haystack Rock. Son and I were doing some secret teaching (I was teaching but he didn't know) about types of caves and we went to the Sea Lion Caves one year.
http://www.sealioncaves.com/tickets.php
We also did the Ape Caves on Mt St Helens and one up by Boundary Dam (Canada/Washington border)