What type of engines could be put inside of a Honda crx?

What type of engines could be put inside of a Honda crx?

Another CRX engine. Swapping engines in a front drive car with one that didn't come from the factory in that car is a very expensive & complicated project.

Almost any engine ever made will fit easily in the large cargo area when you open the hatchback. If you are feebly attempting to ask what engines will actually fit in the engine bay in place of the original engine to propel the car, there are numerous books and other sources online for this easily ascertained information. If you are unable to figure out how to use an Internet search engine, you are quite simply incapable of performing an engine swap anyway.

You did not say what year for the CRX so read this guide:
http://www.importinsider.net/2012/02/03/honda-engine-swaps-101-what-fits-into-what/

While I agree with James M., you wanna keep it Honda. Any Honda 4 cylinder engine can be swapped into it.