What exactly do you have? The older FL/FD (all manual) systems have somewhat more value nowadays than they used to because of some cameras which can adapt them. The "key" is the "register" that is the distance from the sensor (film) to the lens mount.
The old FL/FD mounts are too short to be adapted to the newer Canon electronic (EF mount) bodies. But they CAN be adapted to Sony, and to the new Canon "M" mount (mirrorless) of which I now have an M-50
Here's the M50 with an old Canon FD 50mm f1.8 and adapter. The M50 has a VERY short register
View attachment 1715639348
Of course this has to be operated all manually that is manually focus and manually set aperture. On some lenses/ some cameras, you CAN get some amount of "automation" b shooting in Av (aperture priority) where the camera light meter sets shutter. This does not work well with all cameras, with all lenses, or even at all F stops on some lenses
That is a big disadvantage with Pentax / Nikon bodies. They have a long register and cannot be adapted to most older lenses
