Revive Adserver - The free open source ad server formerly known as OpenX Source
Google Ad Manager - Grow revenue wherever your users are with an integrated ad management platform that surfaces insights for smarter business decisions.
Broadstreet Ads - Broadstreet is the premier ad management platform for news publishers, trade magazines, radio...
Kevel - Kevel's APIs make it easy for engineers and PMs to quickly launch a fully-customized, white-labeled, server-side ad server.
OpenX - Ad technology platform available as a hosted service or as an open source download.
Epom - An ad serving solution for publishers, advertisers, ad and affiliate networks