Tchaikovsky
Alexander Pushkin wrote Eugene Onegin.
Yes, he wrote an opera by that name.
Don GiovanniDon Giovanni has elements of opera buffa, but he called it a dramma giocosa, or a humorous drama. Cosi Fan Tutte is an opera buffa by Mozart.
He never wrote an opera.
Mozart
Wolfgang Amadeus Mozart wrote the music for the opera Così fan tutte.
Andrew Lloyd Webber wrote this modern opera.
There is a misunderstanding that John Gay wrote an opera called The Beggar's Opera. This is not the case. Gay was born in Barnstaple, Devon , England and was a poet, not a composer. The words to The Beggar's Opera were written by Gay but the music was by Pepusch ( a German composer )
The opera Mefistofele was written by the Italian composer Arrigo Boito.
Gaston Leroux wrote the original book of Phantom of the Opera, but it was later made into a film/play by Andrew Lloyd Webber, who also wrote the music for it.
There is no such thing as "Tosca a Puccini Vordi Mozart Rossin", but Puccini wrote an opera called Tosca; and Verdi, Mozart and Rossini were composers.
Pyotr Tchaikovsky