Besides miracles and sunshine, you mean?
Peanut M&Ms are a pretty good choice, but they can get melty and covered in fuzzers. Most foods wouldn't hold up. I have fairly sweaty pockets.
Jesus, I don't know. Probably money, as stupid as that sounds. Not coins, they're heavy. But just like a big ass wad of bills. I know that isn't all that creative, but I'm a little short on cash right now, so a full anything, be it matchbox or swimming pool, is going to have to be cash money.
Other than money, maybe like a pocketful of boner? That usually means good times are afoot, or at least I'm looking at something that isn't total suck. Those are usually good times, unless it's one of those, psychologically painful, "Why can't I have sex with every thing that moves in a skirt?" type boners. That's a pocketful of regrets, right there.
Why can't we have sex with anything? Wouldn't we all be a little happier? Yea, each of us would get a little bit of dick we weren't all that keen on once in awhile, but if we just all rolled over for the process, then we'd get an equal amount of sex we'd never have hoped for. Sure that middle-aged Asian woman is on her way to the grocery store, but I'm curious about why that skirt is sitting up so high. Could be a diaper, could be a great big fat ass. And if she's curious about why I've got a pocketful on some other day when I'm busy, I'll let her tag me back.
I guess the problem with this free sex for sex theory is that super hot girls don't want sloppy fat dudes making requests all the damn time. And you just know that sloppy fat dudes will ruin the system for everyone, trying to get at ten and twenty skirts a day. Never mind.
Short Answer: I'll bet a bazillion men have thought the same thing, and I bet my theory on how to make it work is one of the worst and most vague.