First of all, a two stick kit of ram will run in dual channel mode which is faster.
Is there a reason for wanting one stick?
Virtually all ram with the same specs will perform the same and typically has a lifetime warranty.
Fancy heat spreaders are useless and are mostly marketing, avoid them.
You want documented ram compatibility. If you should ever have a problem, you want supported ram.
Otherwise, you risk a finger pointing battle between the ram and motherboard support sites, claiming "not my problem".
One place to check is your motherboards web site.
Look for the ram QVL list. It lists all of the ram kits that have been tested with that particular motherboard.
Sometimes the QVL list is not updated after the motherboard is released.
For more current info, go to a ram vendor's web site and access their ram selection configurator.
Enter your motherboard, and you will get a list of compatible ram kits.