Two that I saw last year who impressed in the few passes of theirs I saw roadside:

Jan Solans (younger brother of Nils, who himself was hanging with the works R5 Skodas in Spain) - dominated Spanish RC4 last year.

Jean-Baptiste Franceschi looked superb in GB and Spain in RC4 too, but hasn't been particularly dominant. No idea on his plans for this year; JWRC or French Champs in an R5, but hope to see him out and about somewhere.