I forgot my glasses in the hurry to work today, so I might be more susceptible to this than usual, but some of the contrasts are very low. For instance palette 14 the yellow links on white, or palette 10 the yellow links on green, are both impossible to read. Update: Contrast 1.02 according to devtools in firefox. Other than that I like the palettes.
Great effort on the site though - was fun to look through to look at some options.