A compass table with a hundred or so tiny compass needles displays the magnetic field of a bar magnet, or two attracting or repeling magnets, for overhead projection. The compass table replaces the old iron filing magnetic field demonstrations (which are still available).
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Compass tables are also used to show the magnetic fields of a long straight wire, a solenoid coil, and a current loop (see Solenoid and Loop Fields [1] and Parallel Wires [2]). The "magniprobe" is a tiny bar magnet completely free to rotate on gimbals in any direction. It will display the three dimensional form of the magnetic field of a bar magnet, delighting the instructor. However, the device is too small to be seen by more than a few students at once unless enlarged on TV. The "Mark II" version of the magniprobe is sensitive enough to detect the earth's field.
Links:
[1] https://demoweb.physics.ucla.edu/node/238
[2] https://demoweb.physics.ucla.edu/node/239