Unfortunately all of Kesha's albums have at least one filler track.
PRISM is filler-free, at least the standard edition. All of the bonus tracks on PRISM are kind of filler material, imo.
The Fame Monster has no filler whatsoever. Neither does the standard edition of Born This Way.
Standard edition of Pink Friday has no filler, in fact even the deluxe edition(s) all slay. Flawless era.
All of Rih's albums have some filler, unfortunately.