YEAH I NEED HAREM ANd fast growing OP MC  like a The Making of a God Slayer yeah i need that kind of mc + harem :)[url=http://royalroadl.com/fiction/9612][/url]

Well my fics have strong mc's and harems(with actual sex scenes I go into a lot of detail you have been warned lol) hope you give them a chance and thanks in advance for the read! (Links are in my sig )

Well the only thing that it comes to mind is Galactic fist of legend, Earth tactics advanced all of those are op mc in the making + litrpg ( basically you just need to go to the authors profile and all of his works are op mc+harem)
Another work with an op mc and COMPLETE ( yeah i know its really hard to find one of those here) is The jurney of an old soul (Its lesbian harem since the mc is female)
If you need more reply...

Check out my sig. There's harem, and there's growth in the OP (in the sense, they evolve as a character).

The mc becomes op really fast and it does have a harem tag.
https://theonewhoseekspower.wordpress.com

Most of fictions by Scottf14. MC is not OP, but harem is OP a bit in Galatea and 'I hate you master'

Check  out 
https://royalroadl.com/fiction/18173/maxima-online

re: hamster fits

My story will probably interest you.

https://royalroadl.com/fiction/4697/