Finding a definitive list of *all* cars with a 4x100 pattern is difficult because databases aren't comprehensive and manufacturers sometimes change specs within model years or across different trim levels.
To find compatible wheels, you're better off using a wheel compatibility checker website (many exist; just search "wheel compatibility checker") or consulting a wheel and tire retailer. These tools allow you to input your Fiero's year and model and show you wheels that are guaranteed to fit. You'll want to be sure to select your specific Fiero model to take into account any possible variations.
In short, many cars use a 4x100 pattern, but blindly assuming compatibility based on the bolt pattern alone is risky. Always verify compatibility using the methods described above.