There's a Facebook group called simply Funny Signs. Anyone can go look, and 4500 people have joined in order to post funny signs. Be warned that it is a time sink, as you keep scrolling to see the strangeness of modern signs. See, we ignored posted signs for so long that those who create them had no choice but to get creative just on the off chance that you might read one. And creativity pays off!
It's amazing what you can find entertaining if you just pay attention. You can see a roundup of 40 such signs at Bored Panda, or go directly to the Facebook group to keep up with the flood of incoming signs.