According to my new site, the 8 most popular solo girls at the moment are:
1) Tiffany Mars (
http://www.tiffanymars.com
2) Felony Angel (
http://www.felonyangel.com)
3) Raven Riley (
http://www.ravenriley.com
4) Paris (
http://www.playwithparis.com
5) Evilyn Machine (
http://www.evilynmachine.com)
6) Kate (
http://www.katesplayground.com)
7) Candie Crush (
http://www.candiecrush.com)
8) Diddy (
http://www.diddylicious)
I know you said top 20, but I have a mix of pornstars and sologirls in the top list, so this is what you get. ;)