both RTAS and TDM never was open and i´ve never seen it anwhere.
i would think it is the opposite way: for AAX you might find someone sharing his material, but you can not do more with it than programming stuff for yourself. if you publish it without consent, the homeland security special ops visits tomorrow.
for OS9 the number of license takers is below 40(!), of which at least 1 company owner is a scene member. but professionals will have that kind of vintage stuff deleted from their drives long ago.^^
then, as you know, nore more VST2 publishing is allowed unless your registration is older than 10/2018 or whenever that was.
for pluggo you do not need licensing of VST, RTAS, MAS, AU, it was already given to cycling runtime.
same with VSTs containing RNBO code made with max - unless you distribute commercially.
MAS was open like VST, but support and format is long dead.