All just my personal opinion
Beethoven: Piano Sonatas — summary for comparisons of recordings, involving the following artists: Wilhelm Backhaus, Paul Badura-Skoda, Daniel Barenboim, Ronald Brautigam, Edwin Fischer, Emil Gilels, Friedrich Gulda, Clara Haskil, Jos van Immerseel, Julius Katchen, Wilhelm Kempff, Igor Levit, Mikhail Pletnev, Maurizio Pollini, Svjatoslav Richter, Arthur Rubinstein, András Schiff, Artur Schnabel, Mélodie Zhao
Der Ring des Nibelungen, part 4 — comparing 2 recordings: Furtwängler (1953, Rome), with Suthaus, Mödl, Greindl, Poell, Jurinac, Klose, Pernerstorfer, etc.; Janowski (1980), with Kollo, Altmeyer, Salminen, Nöcken, Sharp, Wenkel, Nimsgern, etc.
Der Ring des Nibelungen, part 3 — comparing 2 recordings: Furtwängler (1953, Rome), with Suthaus, Patzak, Frantz, Greindl, Klose, Streich, Mödl, etc.; Janowski (1980), with Kollo, Schreier, Adam, Nimsgern, Salminen, Wenkel, Sharp, Altmeyer etc.
Der Ring des Nibelungen, part 2 — comparing 2 recordings: Furtwängler (1953, Rome), with Frantz, Mödl, Windgassen, Frick, Konetzni, etc.; Janowski (1980), with Adam, Minton, Altmeyer, Jerusalem, Norman, Moll, etc.
Der Ring des Nibelungen, part 1 — comparing 2 recordings: Furtwängler (1953, Rome), with Frantz, Windgassen, Neidlinger, Patzak, Grümmer, Greindl, Frick, etc.; Janowski (1980), with Adam, Minton, Schreier, Nimsgern, Wenkel, Salminen, Popp, Schwarz
Beethoven: 6 Bagatelles, op.126 — Ashkenazy (1984), Brautigam (2010), Brendel (1964 & 1985), Gould (1974), Schnabel (1937); Beethoven: 24 Variations on the Arietta “Venni Amore” by Vincenzo Righini, WoO 65 — Pletnev (1997), Brautigam (2012); Schubert: Symphony in B minor, D.759 (“Unfinished”) / Symphony in C major, D.944 (“Great C major”) — Furtwängler (1952), Harnoncourt (1992), Dausgaard (2006)