I don't know what to post LOL
for me personally, I think Holsts Planets is a great starting point for classical music. It's probably my favourite classical work of all time.
Masterful orchestration and full of character. Mars and Jupiter are its most famous sections but it's just an incredibly consistant and charming set of work.
For something a bit for subdued, Ravels Piano Trio is an underrated gem, really understatedly beautiful and a very intelligently written work (I wrote an essay on the second movement, it makes inception look like a fairytale.
Personally for me I'm obsessed with the Symphonies of Ralph Vaughan Williams and would recommend them to anyone. All of them are completely different and full of characters and are just perfect so here are a range of examples
Stravinsky's probably the badass of classical music and probably the most influential composer of today. The Rite of Spring isn't the easiest thing to listen to, but it's a terrific and highly inspirational work.
Something a bit more jazzy? Gershwin is the way forward
Pretty piano music? Look into French impressionists, Debussy, Ravel, Satie
...there's alot there now, but I can go on for ages.