A new interesting extension system for Scratch that may be worth looking for Poppy Creatures: ScratchX at
http://scratchx.org/#home
Additional links to ScratchX and their extensions:
http://scratchx.org/#extensions
http://ericrosenbaum.github.io/tone-synth-extension/
Make!Sense
http://www.makesense.co/
http://creativecomputerlab.com/makesense.html#datamodeinstructions