Unfortunately I don't have pictures, but there is a wild patch of Opuntia ficus-indica where my mom lives in California. It's massive - probably 20+ foot across in some spots - and must have been planted many, many decades ago. The base of them look like tree trunks now. There are a handful of absolutely gigantic individual plants of this species. I'd keep an eye on the fruit til it ripened, then mom and I would go pick the tunas, since she likes to make drinks out of them, and I would periodically harvest the young pads because I loved to sautee them and have them with egg dishes.
Just yesterday I was trudging through town in the area of this reasonably well-gardened lot on a corner which I go out of my way to walk by. They have a significant hedge of Pitanga which fruit frequently and it looks like every single fruit I don't pick up rots, so I've collected a lot of seeds from there. But there is also a wonderful, rather large Opuntia Cochenillifera which also fruits frequently - and same deal as with the Pitangas. Anyhow, people must just be idiots, because when I walk by I always see a multitude of broken off pads (only on the street side of it, of course), many of them injured badly. I don't do the car thing, so I'm always carrying a backpack or a basket or somesuch, and I had room in it time so I gathered a couple of the best looking broken-off pads. I've been wanting to find an Opuntia that will do well in the very wet, humid tropics where I live and that one has been the healthiest and most productive that I've seen, so I'm looking forward to seeing how it will get on at my place.
PS: Is there something awry with the "Add image to post" function today? I can't seem to get it to work for the life of me.