I really like watching the German bouldering team training videos--I think there are 4 long ones and one short one? They are great for ideas of interesting ways to crosstrain. (And then, of course, you fall down the youtube rabbithole of climbing videos.)

This also got posted to another forum I'm in: https://www.facebook.com/thelaurenabrahamfanpage/videos/1152359758128805/

Also I have never tried it but the rice bucket training thing for hands/forearms: http://www.dpmclimbing.com/articles/view/way-iron-fist