Rarely is it appropriate to need ALL of these things, and it’s not often necessary to go shopping, just use this as a guide. If your shoot involves print modeling looks, this may not be a complete list.
Women
Any favorite clothes that you look great in.
Jewel-Toned and Neutral Palette mostly - Color is good!
Mostly solid colors, but some pattern can be good for layering
Simple things like solid T-shirts can often be best
Layering Pieces like jackets, cardigans, blazers
A business look or quirky look can be great if you tend toward supporting roles- possibly glasses
A FEW accessories that might complete an outfit like scarves and jewelry
Any favorite clothes that you look and feel great in
Neutral undergarments
Some character looks that are often suggested to me: vintage quirky, blue collar worker, waitress, CEO, lawyer, law enforcement, sex pot
Men
Mostly solid colors, but some pattern can be good for layering
Button up
Flannel
Henleys or waffle-knits
Solid crew neck T-shirts
Jackets, blazers, sweaters
A suit if this is appropriate to you
Some character looks that are often suggested to me: blue collar worker, outdoorsy guy, CEO, lawyer, law enforcement