Most aren't worth much. However there are a few that might be worth something.

For example, the original POTF2 figures in 95 (with the red blade cards) had a few error products. For example, after the initial batch, they decided to make the lightsaber blades shorter. There was a brief period of time when they packaged the short blades in the old long trays. There was also something about boba fetts with different paint jobs on his hands (circles or no circles etc) Those used to be worth a lot but I don't know about anymore.

I don't know about the newer stuff