Duncaaaaaan

don't forget all those wonderful waltzes he made!

Waltz of the flowers
Waltz from swan lake
Waltz from Eugene Onegin
Waltz from sleeping beauty
And, his 1812 overture, is really good.

Oh and seeing that you like the Fidelio overture, why not try Beethoven'sother overtures?

Coriolan overture
The creatures of Prometheus
Egmont (my favourite!)
Leonore no.3
(theres a whole load more)

Plus, there are Beet's nine symphonies,

his 5th symphony is really good and I'm sure you would have heard it before his 9th is just magnificent, the last movement, Ode to Joy, is just staggering. My favourite though is the 7th symphony, the 2nd mvt in that is BEAUTIFUL!

Rossini is an italian composer, he made stuff like:

william tell overture, I'm sure you'll love that and you've probably heard it before.
Barber of seville overture, again this is a well known piece.

Then there's Edward Elgar, an english composer. He did some lovely pieces like:

chanson de matin
chanson de nuit
Salut d'Amoire
Enigma variations
The cello concerto (listen to Jacqueline du Pre's recording!)

Dvorak:

All his symphonies, his new world symphony is the best though
Cello concerto in B minor (again, Jacqueline du Pre's is the best)I prefer this to Elgar's tbh.

Mozart, perhaps the most well known composer of all time:

Don giovanni overture
The magic flute overture
The marriage of Figaro
All his symphonies, his 40th is just great to listen to, and his 41st is also lovely.