Frank Clark is another obvious one, Pat Heard was also on the bench for Villa and Dietmar Hamman when Benitez was managing. Howard Gayle was another one on the bench for Liverpool. Ian Rush played for us too.
Add in Andy Cole and Nicky Butt - in the same team was Ronny Johnsen who played about 3 times for us.
Kluivert did for Ajax.
Does Geremi on the bench for Real Madrid count? I know he strolled around the pitch for us but don't remember him actually playing as such.
An easy one to overlook is Ronnie Simpson who did it with Celtic in 1967.
As an aside, we have 3 managers who did it as players, Dalglish, Souness and Gullit.