I reckon the i5-8600K looks like an astounding good value & good performance gaming CPU, probably the best performance for dollar of the whole lot!  I think you've gotta go with an overclockable CPU, another 15 or 20% performance through overclocking is something you don't want to miss out on, because high clocks are still one of the best way to maintain very high frame rates in games, e.g. 144fps+.  The only two CPUs worth purchasing in my eyes are the full fat i7-8700K and then the i5-8600K if you're on a bit more of a budget.