Thank you for your help!
First I did registered Gambling7. But then I thought… hum… the ing part may be easily forgotten… Then I remembered that casino, poker, bingo and sports betting are really just online games, and I thought that could also be a good domain, even if it’s a bit longer…
The domain is just for our industry, and not other kind of games. When I said all kinds of games, I should have said all kinds of “betting” games 
The written opinions here prefer Gambling7, but the poll users voted more for OnlineGames7. Wow, I still don’t know which one to choose…
Thank you!!!