Advice on new strapon heads

So the strapon harness we have has removable dildos. Currently we have one thats 5 inches long and "normal" penis shaped. We're looking for something thats 1) a bit bigger and 2) a bit more exciting. The idea of a tentacle or knotty one sounds really good to both of us, but we're not sure what actually feels good.

Any help would be amazing!