I have been collecting these for a while. It's a mirror of my list over at http://www.stephanmiller.com. I haven't got to categorizing them yet.

http://121media.com/
http://247realmedia.com/
http://7adpower.com/
http://accelerator-media.com/
http://adagency1.com/
http://adbonus.com/
http://adbrite.com/
http://addynamix.com/
http://adforce.com/
http://adhearus.org/
http://adknowledge.com/
http://adlink.net/
http://adorigin.com/
http://adpepper.com/
http://adsmart.net/
http://adtegrity.com/
http://advertising.com/
http://adworldnetwork.com/
http://adzuba.com/
http://affiliate-program.amazon.com/gp/associates/join
http://affiliatefuture.co.uk/
http://affiliatesensor.com/
http://allclicks.com/
http://allfeeds.com/
http://ampiramedia.com/
http://asn.com/
http://avnads.com/index_avn.php
http://axill.com/
http://azoogleads.com/
http://bannerboxes.com/
http://bannerconnect.net/
http://bannerspace.com/
http://bclick.com/
http://bidclix.com/
http://bidvertiser.com/
http://blogads.com/
http://bluelithium.com/
http://burstmedia.com/
http://casalemedia.com/
http://cbprosense.net/
http://chitika.com/
http://cj.com/
http://claxon.com/
http://click.absoluteagency.com/
http://clickagents.com/
http://clickbank.com/
http://clickbooth.com/
http://clixgalore.com/
http://clickhype.com/
http://clicksor.com/
http://clickxchange.com/
http://commissionmonster.com.au/
http://coverclicks.com/
http://cpxinteractive.com/
http://creamaid.com/
http://crispads.com/
http://darkblue.com/
http://dmoglobal.com/
http://drivepm.com/
http://emarketmakers.com/
http://euroclick.com/
http://experclick.com/
http://expoactive.com/
http://fastclick.com/
http://federatedmedia.net/
http://gold-group.com/
http://gorillanation.com/
http://heragency.com/
http://hispanoclick.com/
http://google.com/adsense/
http://hurricanedigitalmedia.com/
http://hyperbidder.com/
http://impressionup.com/
http://industrybrains.com/
http://interclick.com/
http://interevco.com/
http://joetec.net/
http://linkshare.com/
http://mammamediasolutions.com/
http://maxbounty.com/
http://maxonline.com/
http://metareward.com/
http://mirago.com/
http://miva.com/
http://nixxie.com/
http://onemonkey.com/
http://opt-media.com/
http://oridian.com/
http://oxado.com/
http://payperpost.com/
http://paypopup.com/
http://peakclick.com/
http://pheedo.com/
http://pointroll.com/
http://popuptraffic.com/
http://premiumnetwork.com/
http://pricegrabber.com/
http://profitcenternetwork.com/
http://publisher.yahoo.com/
http://quakemarketing.com/
http://quigo.com/adsonarexchange.htm
http://quinstreet.com/
http://qumana.com/adgenta.htm
http://realcastmedia.com/
http://realtechnetwork.com/
http://responserepublic.net/
http://revenue.net/
http://revenue.net/
http://reviewme.com/
http://rightmedia.com/
http://robertsherman.com/
http://rydium.com/
http://shareasale.com/
http://shopper.cnet.com/
http://shopping.com/
http://strategicaffiliates.com/
http://targetpoint.com/
http://text-link-ads.com/
http://textads.biz/
http://textwise.com/
http://tmp.com/
http://tradedoubler.com/
http://tremornetwork.com/
http://tribalfusion.com/
http://ttzmedia.com/
http://valuead.com/
http://vibrantmedia.com/
http://waypointcash.com/
http://webadvertising.ca/
http://websponsors.com/
http://whenu.com/
http://yesadvertising.com/
http://zanox.com