the most 'complete' sample pack I know of is from Red River. they have an extensive line of papers and the sample pack is dirt cheap.
there are too many papers on the market so first figure out what look you want and how much you're willing
to pay per sheet. You may love Epson EEF but it's very expensive. You'll find that you'll tend toward
gloss or lustre or matte etc etc. Then you can get more specialized sample packs.