If the concern was no aftermarket cooler providing warranty I think that intel cooler I mentioned would fit the bill. Intel would have a hard time denying a warranty using their cooler with their cpu and both cpu and cooler are covered by a 3yr warranty. Using a larger cooler designed for overclocking isn't going to help retain the warranty since intel doesn't warrant their cpu's for overclocking purposes anyway.
There's no guarantee written anywhere that a k series chip (any of them from any generation) are guaranteed to reach x amount over stock speed out of the box or warranty that reaching such speeds with any voltage over default is covered by warranty protection. Worrying about an aftermarket cooler for overclocking and warranty retention, that ship has sailed.
Edit: on cpu overclocking (regardless of cooler choice)
https://communities.intel.com/thread/60979?start=0&tstart=0
If concerned about overclocking there's an additional performance tuning protection plan people can purchase and applies only to boxed retail cpu's (oem/tray don't qualify) that allows for a cpu replacement during the 3yr warranty period if running the cpu out of spec (aka overclocked or underclocked). It's not covered under the standard retail warranty though.
https://click.intel.com/tuningplan/
The plans run anywhere from $20 for a 4690k to $25 for a 6500k/4790k to $30 for a 6700k and are good for 1 cpu replacement due to oc damage.