Leonora in 3 of Verdi’s operas, Oberto, Forza and Trovatore, and also in Donizetti’s La Favorita.You mean these are two different people?
There's Ferruccio Tagliavini and Roberto Tagliavini.
And moving away from singers and onto characters, what about those similarly named bel canto heroines: Adina and Amina? Elivira is a character in I Puritani, Ernani and Don Giovanni. Rodolfo is the hero of both Luisa Miller and La Boheme. And let's not get into all those English queens, Elisabetta di Whatnot anyone?