Individual artists, bands, labels and distributors sell new stuff from all genres on https://bandcamp.com/
It's not entirely comprehensive though, it's often not the best for choice of back catalogue titles.
The public and shops sell new and second hand stuff of all genres on https://www.discogs.com/
Discogs will also allow you to keep track of what you have and what there is out there? It includes the details of the different presses of the same title.
It's useful for reference. If you're even semi serious about collecting tunes you'll likely use Discogs a lot.
If you wander into a record shop, or look at a stall in a market or record fair, here or abroad? They may well sell on Discogs and/or E-Bay, just ask?
Obviously check feedback on a vendor that's new to you, as you would with other internet marketplaces.
E-Bay is E-Bay. Use your loaf. If it looks too good to be true? It probably is.
Then there's the shops.
Bicks mentioned https://www.normanrecords.com/
ChrisP likes https://spillersrecords.uk/new-releases-2024/
I quite like https://www.juno.co.uk
New Jazz and Classical https://www.prestomusic.com/
A couple of faceless ones that can be useful are Music Magpie and Rarewaves.
You'll find them selling on a couple of the marketplaces or direct. It may not always be better to buy direct? Sometimes there's dynamic pricing?
Rarewaves can be slow, but it's been by far the cheapest on a couple of US titles I was after.
Ordering from labels is pretty cool when they're in the UK.
When you see what happens with P&P and tax on imports, you may want to look for a vendor in the UK?
Have a look at some of those. Come back with any questions you might have?