• fameboy,
• vameboy,
• bameboy,
• hameboy,
• yameboy,
• tameboy,
• gmeboy,
• gameby,
• gaemboy,
• gambeoy,
• game boy,
• gamee boy,
• gameboye,
• game booy,
• gemboy,
• geme boy,
• gamoboy,
• gamebuy,
• gamebeoy,
• gam boy

The adjective form of the word "Gameboy" would be "Gameboy-ish".

The plural form of the word "Gameboy" is "Gameboys".

The singular form of the word "gameboy" is "gameboy". The word is a proper noun that refers to a specific brand and product, so the singular and plural forms remain the same.