Welcome to the Lubuntu community @meetdilip
I’m don’t know where the best place to talk/discuss themes & configuration settings for LXDE is, but this site is appropriate for Lubuntu 
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Many of us on Lubuntu use the newer LXQt desktop (Lubuntu 18.10 & up), so what works for us may not work for you, and vice-versa. The switch from one desktop to another does sort of split our community a little for desktop specific (like themes), however many things (eg. openbox) remain pretty much the same regardless of LXDE/LXQt.
The best resource for Lubuntu (LXDE) themeing is likely https://help.ubuntu.com/community/Lubuntu/Theming which includes a few places you can go for resources.
I can’t offer more, I’ve a directory on a server where i’ve put themes I’ve liked over the last decade+ (most will be from gnome-look.org ), copy them to a new machine & just pick one I think will work for me. (my screenshot will show I’m not gifted aesthetically )