Creator/Pam Grier was one of the pregnant women trapped in the building by a hurricane.
Dick Butkus was another woman's husband in those same episodes.
Leon, the young shoeshine boy that Harry adopted in season 3, later grew up to be Bumblebee & Dwight.
Al Craven, a sleazy tabloid reporter who hassled the gang a few times during the first two seasons is the titular Bernie.
Estelle Harris, best known as George Costanza's mother on Seinfeld played a hooker that got arrested with Christine's father in season 3.
Bull's girlfriend in one episode was played by the diminutive Denny Dillon, from Saturday Night Live (during its notoriously awful sixth seasonnote much like Eddie Murphy and Joe Piscopo, Dillon was one of the few cast members who was genuinely funny during that season despite being given material that wasn't, but she ended up getting fired after Dick Ebersol took over) and the HBO sex comedy Dream On.
Michael Richards as a man who thought he was invisible.
In the Season 2 episode 'Nuts About Harry', James Cromwell and Kevin Peter Hall.
TeriHatcher as Dan's superior's niece whom he's supposed to "keep out of trouble."
Ellen Foley, who played public defender Billie Young in season 2, sang back-up vocals for Meat Loaf. Her best known vocals are on "Paradise By the Dashboard Light" ("I wanna know right now / Will you love me forever?")