Greasy Fork is available in English.
Show password when mouseover a password field
< Show Password on MouseOver 피드백
Wow... I really missed to check comments here. Sorry. No notification via mail to me... dunno. Yes, there were some cases where JS generated fields were missed to reveal the password or simply blocking scripts like his. I recently (now) updated the script, because I found one service in my company to do exactly this, but more advanced. The new update also resolves this.
Just curious about your comment "...I simply made sure it really works on (almost) every password field..." -- how does your version improve on LouCypher's?
e.g. are there any cases where you found his didn't work?