Solution
Unless explicitly stated in the specifications sheet, such as with the
PCIe-8361 that ships with a low profile bracket, NI PCI(e) cards do not ship with or fit a low profile bracket. The low profile bracket, roughly half the height of the standard bracket, can be used to fit the device in newer small form-factor (SFF) desktop cases or in 2U rack-mount cases.
We do not sell these brackets individually, but since the low profile bracket adheres to the PCI/PCIe standard for such brackets, it's possible to acquire these brackets from a 3rd party vendor.