a must have is #5 which is designed for powder. i've used it w/her dual powder foundation & loose powders & the finish is excellent.
as for e/s, #21 & 29 are must haves IMO. you can get a push liner brush from almost any art supply store so don't bother w/hers if @ all possible.
lastly, #2B is a great blush brush. applies blush, bronzers & highlighters wonderfully for a polished look.