Many other amateur erotic sites with less popularity are listed on Wiki:

Abbywinters.com
Adult Film Database
Adult FriendFinder
Adult Web Movie Database
Alt.sex.stories
Asian Sex Gazette
Babeland
Bang Bros
Bang Bus
Beautiful Agony
Beaver Hunt
Big Sister (brothel)
Carstuckgirls.com
MET ART
MILF Hunter
Masktv
Mattsmodels.com
Porn 2.0
Porn bot
PornoTube
Privatevoyeur.com
Projectvoyeur.com
PureTnA
Sensible Erection
Sex.com
Stile Project
Peter Stringfellow
SuicideGirls
Swank
and more