The Schlagwerk BB110 Buzz Board XL is probably the easiest way to make your cajon a more versatile instrument. With velcro, you 'stick' it to your instrument and easily add an extra string sound.
While cajons are massively fun to play, sitting on one for hours on end eventually becomes a little uncomfortable. Unless it's been fitted with the foldable and ergonomic Schlagwerk ECA70 Ergo Cajon Adapter that is!
The Schlagwerk RTSK MagShake consists of two small magnetic shakers, which you place on either side of your frame drum's batter.
The Schlagwerk RTCH Frame Chick percussion accessory works on either your drum kit, cajon, cajinto, frame drum - or cardboard box!