Just off the top of my head
The big three
FreeEzineBucks - gotta love 'em
Freeticketcash - gotta love 'em
WEGcash - gotta love 'em
CECash - gotta love 'em
The Rest
FreepassBucks - new but looking good
CouponBucks - new, only one popunder
Cash.com - never tried
Datinggold - contact them for info
Insite Adult - excellent webcam niches
Gammacash - $0.60 per email
FreemagsBucks - never tried
Signup4sex - never tried
AdultEarners - great long term concept
ComboCash - $1.50 and $40 upsells
Grogancash/Shinycash - The name sells itself