https://www.bachvereniging.nl/en/about-allofbach
All of Bach is a project of the Netherlands Bach Society. High-quality recordings of the works by Johann Sebastian Bach are made freely available for everyone.
I'd also add Bruckner to the list (my favorites are 4 and 8, and since I like big brass section then the Chicago Symphony Orchestra recordings with Solti fit me well, although I realize many classical music purists will probably disagree with me there).
The Lucerne Mahler 2 is a great performance - but it's also special for other reasons: Claudio Abbado had previously been Chief Conductor of the Berlin Philharmonic but has diagnosed in 2000 with stomach cancer and had to stand down. After severe surgery he was able to return to conducting (I think for the first time) in Lucerne with an orchestra of musicians that were hand picked by Abbado from the world's greatest orchestras and chamber ensembles. So a hugely emotional event as well as a great performance.
https://www.classical-music.com/features/artists/20-greatest...
Some personal favourites:
Brahms 4 - Carlos Kleiber / Vienna Philharmonic (https://www.youtube.com/watch?v=Ho-H-8FzbU8)
Mahler 2 - Claudio Abbado / Lucerne (https://www.youtube.com/watch?v=4MPuoOj5TIw)
Shostakovich Symphonies - Bernard Haitink / London Philharmonic / Concertgebouw (https://www.youtube.com/watch?v=YS4dcZ90fN0)
One thing to look out for in baroque is original instruments vs modern instruments performances. Original instruments have a very different - leaner - sound. I find I much prefer them now. Someone like John Eliot Gardiner is amazing in original instruments Bach.