Below are some professional horn players to check out.
Performers to look for: Hermann Baumann, Froydis Ree Werke, Barry Tuckwell, Dennis Brain, Alan Civil, Phil Farkas. Composers and standard repertoire: Mozart concertos, Vivaldi, Telemann, Brahms Trio (horn, violin, piano), Richard Strauss. Specific recordings of interest: All brass quintet recordings are excellent; Horn Club of Los Angeles recordings - works for multiple horns (even 40 or more!); Baumann Mozart Concertos on natural horn (no valves: half-steps achieved by moving the hand in the bell), Tom Bacon, Rick Todd (he plays classical and jazz).