The boards mentioned below are not LGA1151, of which the OP is ask.
The consensus that I've read in these threads is that the Z170 chipset does not handle more than 4 cards very reliably/at all.
Thats why I posted links to other chipsets, the Z170 chipset will only handle 3 or 4 cards depending on the board. OP stated "maybe a socket 1151 mobo."