I've used the tip of a toothpick's worth of olive oil a few times in the past. I probably won't be doing that again.
I believe I've heard of eggs or egg whites being used, as a clarifying agent? Haven't tried it myself.
Fish bladders, anyone?
Seriously, though. It just goes without saying that we each have our own particular taste preferences, so anyone can really use anything they want in any beer, for any reason, who cares. Anything else is just "naziism". Just because I might say "you're wrong!" or you might tell me "you're wrong!" doesn't mean either of is truthfully wrong about anything. It's only beer.