One thing you can do is create ragdolls for use. Generally, I like to pose them, the main use for ragdolls, but you can, I don't know, fling their bodies around or use other mods such as Gibmod to dismember/decapitate them, especially creatures you don't like (like some ugly Maxis creatures like Fishballgirl or Bigeye Sister).
There isn't much Spore-related things in Garry's Mod, but I eventually took advantage of the built-in Collada exporter in

Here's a pic of it. For those living under a rock: it's on the right.

I don't really take requests because it's fairly time-consuming to make ragdolls, even if I have access to the rig (but I'd like morphers and built-in animations too...; I had to make facial morphers from scratch). But if anyone's interested, I may or may not write a tutorial on how to get a Spore creature ragdoll to Garry's Mod, right from the creator editor to a fully-functioning ragdoll with facial flexes and finger-posing.
Also, I think someone else made a Grox prop for Garry's Mod, but I can make that into a working ragdoll! But if there is a way to export these creatures more efficiently and even allow us to export buildings, vehicles, and even Adventure props from Spore, it would be great!