Most (classical) composers had one or a few lyricists with whom they preferred to work:
Arrigo Boito in his later works
Luigi Illica and Giuseppe Giacosa
Contamine, Plato (when composing Socrate: Platon s'avère comme un collaborateur parfait, très doux, jamais importun - "Plato shows himself a perfect coworker, very soft, never out of line")
Federico Romero and Guillermo Fernández Shaw
Tim Rice, followed by Don Black