All just my personal opinion
Beethoven, “Eroica”-Variations op.35, Comparing recordings with the following artists: Artur Schnabel (1938), Glenn Gould (1970), Svjatoslav Richter (1970), Emil Gilels (1980), Konstantin Scherbakov (1984), Alfred Brendel (1985), Olli Mustonen (1993), Ronald Brautigam (2010)
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)
Beethoven, 12 Variations on “Das Waldmädchen”, WoO 71 — comparing recordings with the following artists: Emil Gilels (1968), Vladimir Ashkenazy (2006), Olli Mustonen (1993), Ronald Brautigam (2010)
Beethoven: Violin Sonatas — Summary for comparisons of recordings, involving the artists Busch/Serkin, Capuçon/Braley, Faust/Melnikov, Grumiaux/Haskil, Kremer/Argerich, Menuhin/Kempff, Mullova/Bezuidenhout, Oistrakh/Oborin, Perlman/Argerich, Perlman/Ashkenazy, Szeryng/Rubinstein
Beethoven: Sonata for Piano and Violin No.8 in G major op.30/3 — comparing 8 recordings: Capuçon/Braley (2009), Faust/Melnikov (2008), Grumiaux/Haskil (1957), Kremer/Argerich (1994), Menuhin/Kempff (1970), Oistrakh/Oborin (1962), Perlman/Ashkenazy (1975), Szeryng/Rubinstein (1961)
Beethoven: Sonata for Piano and Violin No.7 in C minor op.30/2 — comparing 7 recordings: Capuçon/Braley (2009), Faust/Melnikov (2008), Grumiaux/Haskil (1956), Kremer/Argerich (1994), Menuhin/Kempff (1970), Oistrakh/Oborin (1962), Perlman/Ashkenazy (1975)