An emulator is a computer program which lets one computer (the host) run software created for another type of computer (the guest).
The best Gameboy emulators are the same ones that work with the best NES emulators and vice versa. It’s not really possible to use an Android phone to play just Game Boy games. Most are designed for PCs, as they were primarily made only for PCs in their original form. The listings you’ll see on Google Play appear to be mostly scam websites, or copied content without permission from the repositories where they were originally hosted.”