Not sure if it is all of them, but for example the FreeBSD10.2 release announcements lists AMIs for 9 different AWS regions, as well as images in various format

Not sure if it is all of them, but for example the FreeBSD10.2 release announcements lists AMIs for 9 different AWS regions, as well as images in various formats for Azure, Compute Engine and Vagrant. And even before they were part of the official release build, there were AMIs available, built by cperciva, in multiple regions for many, many releases (7.4/8.2+/9.0+) - but you had to know where to look for the ids (or use google).