Bach Cantatas - Rilling (1383 tracks, total time: 2 days) Performed by Helmuth Rilling and Bach-Collegium Stuttgart, recorded during 1969-1985. Sorted by BWV number. The most complete set on Spotify so far.
Bach Cantatas - Suzuki (986 tracks, total time: 1 day) Performed by Masaaki Suzuki and his Bach Collegium Japan. An ongoing project. The latest recording, Vol. 47 was released last month. Arranged in numerical order of the recordings.
Bach Cantatas - Gardiner (1029 tracks, total time: 2 days) Performed by Sir John Eliot Gardiner, Monteverdi Choir and English Baroque Soloists. All recorded during Gardiner's transcendental Pilgrimage in year 2000, the releasing progress in still going on. Arranged in numerical order of the recordings. Press Ctrl (Command on Macs) + G to browse in album view
Update: Three more complete sets on Spotify, by Harnoncourt & Leonhardt, Leusink, and Koopman.
Some useful sites: the Wiki page, the "official" Bach Cantatas, A Listener's Guide, Haenssler page for the Rilling set, BIS page for the Suzuki set, and Cantata Finder for the Gardiner set.
BTW according to Spotify, they are "currently experiencing some problems with playlists not loading normally". If you find these playlists empty or incomplete, just subscribe to them, then restart Spotify. Enjoy the eternal blessings of Bach, with Spotify.