Gay men are probably the best niche there is, although I wouldn't call "gay" a niche, "bears" would be a gay niche.
Gay men are:
usually white-collar, most attend college.
when 2 of them are "partners" both usually work and there are no kids to suck up the $$.
And they seem pretty horny.
I tried to do a gay tgp, it would be really easy to be close to the top considering how few there are, but my heart just wasn't in it.