Based on Mr Smith's post over here, I am inspired to make up my own list. Just as a warning, this is completely opinion based and you probably won't agree (and you probably will). But I am a man entitled to my own opinions.
Yeah, she's just an extra ranger and starts out villain even. But hell, Mele is one of the more developed villains and it keeps the Gekiranger interesting. Since she starts out villain, she's able to get a sexy outfit from get-go, but aside of that, I like her bipolar attitude of starting out cold hearted with other minions, but is a complete fangirl on Rio-sama, one that was genuine and proves great for her character development. Her eventual road to redemption and sacrificing her life for the Gekirangers are really great, and not swaying over her loyalty on Rio, so it was all great.
You probably are wondering why I did not include some, but here's some honorable mentions, when females just got on second place because I like another guy more. Or other reasons.
Well that'll be all from me, hope you got a good read!