• demisexuality was coined by sonofzeal and popularized by OwlSaint on AVEN; gray-a was coined by KSpaz there as well; Hezekiah (pianycist/metapianycist) has a nice summary of that history here
• Hezekiah is also the one who coined allosexual during some musings on whether going on testosterone would affect their (a)sexuality
• its romantic counterpart, alloromantic, was coined-slash-popularized by Queenie (queenieofaces)
• lithromantic was coined by Ian (stopanthropomorphizingme), who itself identifies as Stone, to describe its partner
• wtfromantic was coined as a snide joke by Sciatrix (writingfromfactorx), which you can read about here and here
• quoiromantic was coined as a synonym/alternative to wtfromantic by Cor (epochryphal), and you can read more about it in cos #quoi and #quoi bloggin tags (I recommend this post, this post, and this post for summaries)

Additions:

• sex-favorable was coined by Talia, and you can read their reflections on it here
• allosexism was coined by lunasspecto…