You will be able to overclock any unlocked Intel® processor which are the ones ending with the "K" eg: Intel® i7-6700K.
Additionally, the Extreme editions are the ones ending with "X" which are also unlocked. Which means you can overclock them.
Please take into consideration Intel® does not recommend overclocking your processor. You may overclock it at your own risk.For more information about overclocking you may refer to How to Overclock Your CPU with Unlocked Intel® Processors