cat bat and tan can ban pan ran ram man mat rat yak dog log nap cap tap pop top sap gap map fan you Jew say may who hit mit car bar tar jar bus gas the tad bad fad sad fat pat pad hat lap new dew sue sew ask jot pot lot cot dot not are had sat
Mississippi
tattooballooncommitteekeennessraccooncoffeebookkeeper
vacuum and continuum
balloon coffee
Well, there's probably more than three. Right now I could only think of "balloon" and raccoon though, assuming that you meant those double letters have to be next to each other.
Multiplication
Mississippi
tattooballooncommitteekeennessraccooncoffeebookkeeper
vacuum and continuum
bellhop
quizmaster
"a" & "b".
bellhop
quizmaster
balloon coffee
bellhop
quizmaster