Audiovapor has released Electro Bass MIDI Volume 3 which features 250 original, 16 step analog-style bass MIDI loops. The loops were carefully hand-programmed in a wide variety of usable scales, keys, and modes (indicated in filename). Add your own rests and glide to further customize your sound.
Price: $9. You can purchase Electro Bass MIDI Vol. 1, Vol. 2, and Vol. 3 together for $22 (750 loops).