Marijuana is going to be the easiest drug to produce/grow if you were going to sell things. It would probably be the easiest to conceal to if you kept it in a closet or something. You could order grow kits online for shrooms and things like that and try it out, but that is really the only other thing that is reasonable I can think of. The only other thing I can think of that you could probably make is meth like you were talking about earlier and who would honestly want to mess with that shit and it would be 10 x more obvious than growing pot and a lot more work. Think about growing pot again and look into, it would be the wisest choice if you ask me.