Photography software in general.

Photo Mechanic, On1 plugins, and Capture One - there isn’t a single piece of FOSS photography software that is remotely useful for my use cases.

High volume tethered shooting with automatic application of edits and adjustments in separate layers is basically impossible.

Fast culling of hundreds or thousands of images along with applying metadata with templates is also not really possible.

Darktable and Digikam are okay Lightroom replacements, but they don’t come close to touching what is available in the proprietary world. Rawtherapee doesn’t do tethering at all, and isn’t very good at what it does do compared to On1 Photo Raw or Capture One.