They're generally illegal to distribute - they're derivative works of the video game in question, which is copyrighted by someone else, so you need a license from them to distribute your translations.

There's the slight wrinkle that in some cases there's no one with standing to sue you - copyright is a civil matter in most countries, so you can only be sued by the actual copyright holder, and sometimes the relevant company doesn't exist any more, at least in practice. But it's breaking the law and in theory you could be sued.

/IANAL; I worked on a fan translation Jingai Makyou before an official one was announced