Here is a brief list:

2000 Charge
Adult DVD Empire
Adult Paymaster
Adult Webmaster Empire
AdultChamber.com
ASACP
AVN Ads
AVN Online
Badoink
Big Clicks
Black Label Ads
Bos Bucks
Bureau One, Inc.
CCBill, LLC
Clips4Sale
Coldfair Holdings Ltd
Commercegate
Cybersocket
Datinggold
Double Click Marketing
Dreamnex SA
Emerchantpay
Epoch
Euro Payment Group
Evil Angel Cash
Free Speech Coalition
Fubar
Gamma Entertainment
Grooby Bucks
Hotmovies
ImLive
Internext Domain Auction
Jettis
JT’s Stockroom
Medley, Inc.
Metro Money
Millennium TGA, Inc.
National Net
Netbilling
Orbital Pay
PasswordbyPhone
Pimp Mansion
Platinum Bucks
Premium Multimedia, Inc.
Pussycash
Robomail
Silvercash
Space Age Services
Storm Media
Sureflix Digital Distribution
Traffic Dude
Trodat
Trustcash
Utherverse Inc
Verza Facility
Video Secrets
Web Transactions Services, Inc.
WebPower
YNot