I have to respectively disagree; in no way do I want to take anything away from the true greatness of the Beatles, but Zep has rock, heavy rock, blues, jazzy, pop, progressive, and folk-music styles in their catalog. They have 3min songs, 10min songs and everything in between. As far as being musically diverse, I cannot think of another band that has such as a wide range of musical styles than Zep.
Disagree rather strongly.
Skiffle Everly Brothers style ("Love Me Do")
Black Girl Group ("Please Mr. Postman")
Country-Soul ("Anna, Go To Him")
Goffin/King Standard ("Chains")
Tamla Sound ("Money")
Spanish Ballad ("And I Love Her")
Rockabilly ("Honey Don't")
Motown ("You Really Got a Hold on Me")
Country ("Act Naturally")
Dylan-Country ("I'm A Loser")
Acoustical Ballad ("Yesterday")
Folk-Country ("I've Just Seen A Face")
Riff Rock ("Day Tripper")
Folk ("Norwegian Wood")
Orchestral Arrangement ("Eleanor Rigby")
Children's Tune ("Yellow Submarine")
Psychedelic ("Lucy In The Sky With Diamonds")
Psychedelic Rock ("Rain")
Music Hall ("Honey Pie")
Avant-Garde ("Number 9")
Indian Music ("The Inner Light")
Blues Rock ("Come Together")
Gospel ("Let It Be")
This is in addition to dozens of early rock, standard rock, and the Christmas songs the Beatles wrote or covered. I don't even know what box one would put, "Yes It Is", "Michelle", "For No One", "Penny Lane", "Being For The Benefit Of Mr. Kite", "You Know My Name", "Piggies", and many more incredibly original songs.
No one is really in the Beatles neighborhood in diversity.
Jimmy Page may stand alone among the biggest bands for his abilities on electric and acoustic guitar, which along with John Paul Jones' keyboards, gave Zeppelin their diverse sound. But, among their contemporaries the Who are arguably more diverse. IMO, Zeppelin's lack of ballads, softer music, and harmonies really hurt their case as the most diverse ever.