Hmm, you could try in actual games I guess, I see lots of girls playing games when i'm on, it would have to be long distance most likely though. Why do you need a girl who games though? You might end up not even playing together or the same games etc.
I am just saying that right now is the perfect time to find one! You have a social game called Pokemon go which I know you have heard of which is bringing all gamers outside to find! The best part is that if you see them outside near you then they live close by too! I am being totally serious though, play Pokemon go in more congested areas where there are several poke stops and find a girl nearby who is also playing! It is a game that both guys and girls love equally so if anything try it out!
Step one. Acquire night vision goggles. Step two. Creepily stalk through neighbourhoods looking for girls playing games on their pc.. or console if you're into cod. Step 3. ? Step 4. Profit!
I don't know it's kind of hard because online in games its a sausage fest and they likely don't live near you anyway. I assume conventions are pretty much the same. If you find out I'd be interested to know the answer haha. Especially if they're the shy type who mainly keep to themselves and game.