The best cello recordings I have include Starker, Fournier, Rostropovich. All golden era recordings from late 50’s early 60’s.
http://www.classicfm.com/discover-music/instruments/cello/features/best-cellists-of-all-time/
I would add the great Danill Shafran, relatively unknown outside the former Soviet Union. He was considered in the Soviet Union the equal to Rostropovich. He tied Rostropovich twice for first place in important cello competitions. Didn't travel much outside the Soviet Union. One recording he did in the US was the Shostakovich and Schubert (Arpegionne) Cello Sonatas, a very pricey Living Stereo LSC-2553. (I have 15ips 2 track tapes of the recording, probably copied from a safety master.) Almost all of his recordings were done on Melodyia, with a few reissued by western companies. one problem in tracking him down is that his Russian name is anglicized as Danill, Daniil or Daniel, so Discogs shows different listings with each spelling of his name.
For a historical cellist of the time of Casals, there is Emmanuel Feuermann. He died in 1942 at the age of 39 (from complications of surgery on hemorrhoids.) According to wiki, his pallbearers included pianists Rudolf Serkin and Artur Schnabel, violinists Mischa Elman and Bronis?aw Huberman, and conductors George Szell, Eugene Ormandy and Arturo Toscanini. Several wonderful chamber recordings with Heifetz and Rubinstein. Considered by many at the same level as Casals.
Larry