Several things not noted were wing suggestions and specific add-ons, such as capes and hats. However, included are threads asking for customizable gear for the avatars. Threads about customizing accessories are labled "customizable avatars," and threads about designing and submitting your own avatar in the same manner as portrait spaces are labeled "custom avatars." "Blank avatars" refers to a blank slot in the .fsh file for people to add a custom avatar that can be placed into patches. The threads are arranged by the most popular avatar suggestion type the thread includes, if it includes multiple suggestions.
Also, please note that threads are all labeled by what is suggested in the first post of the listed thread.
(Special thanks to Cassiel for graciously compiling this list/revising his old list for us!)