You can still buy the (current model) Apple remote separately from Apple TV; current Mac OS versions still have built in support for the basic media control buttons (pause/play, volume control, maybe a few others) and you can use tools like BetterTouchTool to implement custom actions.
I use mine (previous-gen Siri remote) to control volume, display brightness, display power on/off, and to switch between display inputs, the first using OSC[1] to the RME mixer app and the rest via a trivial Web service I wrote[2] that controls the LG TV I use as a display via RS-232 (which, for UI reasons, is noticeably faster than using the TV's bundled remote for the same tasks, and much faster than using the buttons and OSD to input-switch on my previous, non-TV display).
While I have keyboard hotkeys set up for the same operations on the Mac, I frequently USB switch my keyboard and mouse to other computers connected to the display, with HDMI audio routed via S/PDIF to the same audio interface (RME Babyface Pro), so having "always-on" copies of these controls is handy.
Before the Apple Remote, I considered using controls on a small MIDI digital piano I have within reach for the same purpose, but this way is slightly more convenient in that I don't have to toggle the controls off when playing the piano.
[1] https://archiv.rme-audio.de/download/osc_table_totalmix.zip
[2] https://github.com/jasminetroll/LgTvControl