Beethoven:
Gardiner, P. Jarvi, Immerseel, Goodman-Huggett (Hanover Band), Toscanini, Muti, Harnoncourt, Bohm VPO, Karajan 1963, Zinman. Bernstein VPO, the Naxos hotchpot of Central European orchestras 12, no partials at the moment
(I could have sworn I have more, but I can't think of any others!)
Mahler: Bernstein Sony and Bernstein DG, Tennstedt, MTT, Gergiev, Zinman, Inbal, Bertini, the not complete Levine, and large portions of Boulez, Abbado Chicago, and Rattle. 8 plus Levine, and three partials.
Other composers are considerably less. Brahms is probably the nearest: Eschenbach, Rattle, Muti, Gardiner 4 (no very clear favorite)
Schumann--Kubelik, Zinman, Sawallisch, Vonk 4
Everyone else is no more than two, even Bruckner (Jochum EMI and Wand) and Shostakovich (Haitink, Barshai) although I've got all of Gergiev's and Petrenko's, and if those become completed cycles, I'll have four Shosty cycles.
Non symphonies--only Beethoven really counts here. I've got at least two cycles each of the string quartets, the piano trios, the piano concertos, the violin sonatas and the piano sonatas.
ETA:I've also got what Norrington has released as his series of Mahler and Bruckner recordings . and Chaillys Mahler cycle is part of the Presto order that got lost in transit, so I both have and don't have that one.