UPDATE: SAMPLER INSTRUMENT is now a "track" characteristic; it's not broken; it's still there. Now it's drag and drop from the "pool" instead of a "generator", there's a default sampler track characteristic now. Also, any WAV file dragged onto the work area will trigger a sampler track to be initiated (step editor or mixer channel).
Hmm, OK since FL Studio 24 (summer 2024) all of a sudden I can't add any sampler channels. They just do not show up in any lists anywhere. I'm thinking maybe Image-Line has plans to phase it out. Because that is just really wierd. I know they got a lot of built in plugins, but the sampler was the only one I ever really used!
Good thing I got Hydrogen and Reaper. Damn.
I even tried reinstalling and all that and nothing fixed it.
OOPS, I was wrong, see the update at the top of the page.