most demos (at least the newer/good ones) from fit have a morphos port:
http://www.kameli.net/fit/

Several very nice demos (at least those which have a linux port) from traction
http://pouet.net/groups.php?which=1270&order=thumbup
also have sources available and probably can be easily ported to morphos
(they use sdl, opengl - and for audio fmod which can be easily replaced wiht sdl-mixer -
did so some years ago, to watch/hear those on my pegasos)