be aware that the current and recent generations of intel and AMD chipsets have confusingly similar names. Your's is intel, so obviously intel only CPUs.
The i7-6700 and i7-7700 would be the best. Both are the non K versions so no overclocking as the motherboard will not allow that. Other sensible choices are the i5-6600 and i5-7600...
On AMD, you would need a new motherboard but you cannot go wrong with the Ryzen 2600 or 2700 series. They are great value CPU's and very powerful not only for gaming but productivity...
be aware that the current and recent generations of intel and AMD chipsets have confusingly similar names. Your's is intel, so obviously intel only CPUs.