Judicial estoppel - Being barred taking positions directly the opposite of ones you've taken in litigation before (and benefited from). IE you can't say "we didn't do it" in a civil lawsuit, and then say "we did do it" in a bankruptcy proceeding.

Estoppel by deed - In real estate, f i give you a deed to a house, i can't later turn around and claim it wasn't a valid deed.

Prosecution history estoppel - in patents, if i disclaim something in a proceeding with the PTO to get a patent, i can't later claim infringement for the thing i disclaimed.

IE if the USPTO gives me a prior art reference and says it overlaps, I can say "my patent doesn't cover that" and disclaim rights to the part they think overlaps. I can't later sue someone over that overlap.