Sorry for the long title, but basically what I want is to know if there is some effect or plugin that can automatically make a track pan from left to right repeatedly like this > https://vocaroo.com/11nE22h7iQM7. If there is something that can do this, I have been looking for a long while now, thank you to anyone who can help me.
Assuming that your sound is in both channels of a stereo track,
apply this code using the Nyquist Prompt effect (https://manual.audacityteam.org/man/nyquist_prompt.html)
(setf hz 4)
(let ((left-mod (mult 0.5 (sum 1 (osc-pulse hz 0)))))
(setf right-mod (sum 1 (mult -1 left-mod)))
(mult *track* (vector left-mod right-mod)))
The first line sets the number of times per second to pan.