I can only comment on fiber-base papers. Of those being currently manufactured and that I use, Ilford Galerie and MCC110 have a very bright-white paper base. The Foma graded papers are a bit yellower.
I just printed with Adox MCC, Ilford Galerie and Fomabrom graded and I actually put the white margins of the prints right next to each other. All prints were glossy and my developer was Ansco 130 with benzo instead of bromide. MCC was the brightest, then Galerie, then the Foma. Differences are subtle and require bright, even light to notice them.