Little Scale has released a collection of free sound kits for LSDJ,  Little Sound DJ for the Game Boy.

They are free downloads from his site. 

Here are demo videos for each collection:

Atari 2600 Kit for LSDJ

http://www.youtube.com/watch?v=zp1nCZKHkEI

Debussy LSDJ Action

Sega Mega Drive Kit for LSDJ

Donk Kit for the WAV Channel in LSDJ