I cant remember them now, but there used to he some specific google searches you could do to get even more unsecured cams. Wont lie though, it was really creepy finding cameras people had in their houses, just unsecured.
Yeah I found one of those searches, must have been late 2000s, looks like most of them were in Asia. Mostly streets, supermarkets, but I found one in someone's bedroom (unoccupied) and promptly shat myself.
It bugged me that there was apparently no way to contact the owners and let them know, "hey you should probably do something about this..." This was like, first page of Google, so I'm sure I wasn't the first or the last to find it...
Thankfully, some of the cameras have a speaker you can play audio through. So you can let them know in band. Assuming you speak whatever language they know.