What you can do with them, if you still want to keep them around and not throw it away like myself:
1: Glue or fix it together, use hot water or hair dryer to bend pieces that needs bending, essentially the figure will be a statue once you are done.
2: Use it as reserve parts for future figures of same type.
3: USe it in some diorama and make it to a injured/damaged figure that fits in the diorama. Example: marines shoting and your damaged xeno could act as their target, even better if you modify and add acid looking plastic and the piece thats broken as cut off limb from the marines shoting.
4: Sell it online, there are some people who buy damaged figures, mostly to use as spare parts or for their own custom builds projects.