in your opinion, a similar project with 3d character and after effects, in which category should i put it?
I had chosen “after effects”, but maybe I was wrong.
Also, in tags, I can put used programs, example: houdini?
Don´t put the software you use in tags, it´s not necessary. If you make a 3D character animation to be used just as it is, upload it to Motion Graphics category. Now, if your intention is that your 3D character reaveals a logo, then make an After Effects Project File and upload it to that category.