One of my three cats is black (with a small white 'bib').
His name is Simon, and he is about 12 years old.
I found him on the town square on graduation day for our local university when he was a few months old.
He was already hanging around an older couple who had stopped for a spell on a bench in front of a store. They said he'd been there for an hour or so, and encouraged me to take him home! When he crossed the street to follow me to the electric company to pay my bill, heedless of any traffic, I worried about him. There wasn't any traffic at that time, because most people were at graduation, but I worried what would happen later.
I tried to find someone who recognized him (he had a blue flea collar on, so I knew he'd had some human contact). I finally found someone who was renovating one of the buildings on the square, and he said the cat had been there the day before, meowing to get in. After talking to another guy who had never seen him before, I decided to take the kitty home and put a 'found animal' ad in the paper.
When I got him home, he went right to a pile of laundry to take a nap. And he showed absolutely no agression to my other 2 cats. He didn't even act bothered at all when I trimmed his claws.
I did put an ad in the paper, but was hoping no one would answer it. I decided to be rather vague, so that if I didn't like the sound of the person who called, I could say it wasn't the same cat. I just put "found on square: black cat with collar"(no mention of gender or color of collar).
As I suspected, no one called (I suspected that the collar came from some students who 'adopted' him only as long as they were around, or who just put the collar on him to keep him from bringing in fleas when he visited.
Simon loves the food! And if I don't watch him, he can end up looking like a bowling ball with legs!
He's my oldest, and a big cat, but he still acts like a kitten: playing (though he hasn't done any of his signature own-tail-chasing for a while) and going up to Bobsie (who is 1/2 his size) and bowing his head in front of her so she'll play 'mommie' and wash his head!