What Is The Best Way To Do This?

I need help with this. I already saved for my 7yrs college through 529 prepaid college saving, so as of today he could go to college if he wants to lol. Well, I want save for him cash where he could get access to it in12yrs from now or may be even 16yrs. What is the best way to do that. I looked at Gerber saving plan but isn’t good for taxes reasons. What is the best way?