Solo-Ion
Dungeon Spirit
tAPI was discontinued because of the 1.3 update of Terraria. They've moved development to Prism, a new modding API for 1.3, and someone else is working on tModLoader, another modding API for 1.3.i haven't read all 235 pages of the thread but why was this discontinued?, and if was due to lack of time couldn't some1 else update it?
as i noticed that people say the others use different file types so any Tapi mods don't work with the ones still being updated
I don't know about Prosm, but you can find tModLoader Here.