My gaming cans are
HD558's (which I've still yet to mod into 598's. which is a 2 minute mod which involves removing some stickers inside the cover)
Q701's when I can be bothered to double amp my mixamp with a schiit vali (these are still stock not been bass modded)
I have HD600's, DT770's and a few others but none of them come close to the above 2 for gaming.
I'm still surprised by how good HD595's were for gaming. In the pure bang for buck states you can get a pair of HD595 or HD555's (which can be modded to 595's by removing a sticker) for about £50 these days second hand.
Nothing will come close to them for gaming for that kind of money. You need to buy something from AKG X7XX range for another £100 on top and get a decent amp as well to beat them which is a lot of money for very small improvements.
Everyone will have their own preferences but I honestly think in 90% of cases Sennheiser HD 5XX range are the ones to go for in terms of gaming. Easy to drive, nice open sound, picks out details wonderfully and not too expensive.
If you have a decent amp then get one of the AKG X7XX range.
These also happen to be what I use.
AD700x is supposed to be really good but it's a love it or hate it type of headphone. HE500's I would say would be unbearable for long gaming sessions I owned HE400's and it felt like I was wearing a helmet after a while, they were huge and cumbersome and not the most comfortable of headphones. I would never use my HD600 for gaming so I doubt HD800's or high end audiophile quality stuff is any better. The max you should spend imo is £200 ish for gaming headphones. But the difference between a set of £200 headphones and a second hand pair of HD555 or HD595's for £50 in terms of competitive gaming will be none. That's how good they are at picking out details and identifying footsteps. Just because a can is good for music doesn't mean it's good for gaming. Competitive gaming requires a very wide soundstage, minimal bass and great for detail. Therefore you wouldn't use Basshead headphones for competitive gaming.
If your looking for immersive gaming cans then get DT770's or Fidelio X1/X2's