While we have the vital hardware you have provided nothing specific enough to pick out a new GPU.
Most importantly, how large is the computer and what is the power supply?
Since you have a GTX760 we can assume a certainly level of power, which would let you add anything up to a GTX1060 6GB with relative safety. Not sure about a GTX1070, would really depend on the power supplies' rating.
As for physical size, the GTX760 was available in quite a number of lengths and form factors. Mini cards, as suggested above, are certainly the safer choice for more universal compatibility.
For the games you listed, I would think the GTX760 would be enough.