I assume you are questing for papers for PtPd.
There are some who have tried hundreds of papers, as well as old sweatshirts and license plates from South America. I don't have that much experience, but i do have some favorites that I hope you will try.
Arches Platine
Rising Stonehenge
Fabriano Uno
All are available from Daniel Smith in Seattle. I have ordered online.
Each of these papers requires double coating, an expensive proposition, especially if, like me, you use much more Pt than Pd.
I have found that double coating is unnecessary if you first re-size the papers with gelatin.
Glass rod coating is easy with AP and RS, but bruises the high points of the very textured FU. I use brush coating for FU.
All three papers are very white. AP and RS are smooth and very pretty. FU has a deep linen texture and prominent watermark, and therefore gives a very different look than the former two.
Rising Stonehenge is quite inexpensive--you will wind up paying almost as much for S&H as you do for the paper. You will get 6 8x10 sheets from each sheet of paper, and 4 11x14 sheets. These papers come in much larger sheets as well, but the shipping is prohibitive.
As one who has placed $500 worth of Platinum in the trash, I suggest that you do one thing well, rather than experimenting endlessly, as I did. I would start with Rising Stonehenge. Once you get comfortable with that, then you can branch out to other papers and techniques.
Best of luck!