Is there anywhere i can find a list of games/gaming sites , that already incorporate OfferWalls ?
It's called "research." You need to do research and find out if there are marketing resources that have the information you seek, and you probably need to do the research yourself that you are hoping to purchase. (Research is way beyond and above asking in a forum.) But perhaps you might get lucky and someone may be able to point you in a good direction.
By the way, please be more careful about what forum you decide to post in. This question absolutely did not belong in the Game Industry Job Advice forum, since you already have a job. I'm moving this to the Business forum, reluctantly, since when you said you're seeking new publishers and offered to pay for marketing research, your post approached being an advertisement. Advertising is not permitted in our discussion forums.
-- Tom Sloper Sloperama Productions Making games fun and getting them done. www.sloperama.com
Please do not PM me. My email address is easy to find, but note that I do not give private advice.