Beatles 15 Elvis Presley 7 Rolling Stones 5 Cliff Richard 4 Everly Brothers 3 Gerry & The Pacemakers 3 Roy Orbison 3 The Animals 3 (one as Eric Burdon & The Animals) Peter Paul & Mary 3
and I'm trying to recall if anyone else managed 3. Bob Dylan had 2 of his own plus wrote 2 for others. Many other songwriting teams wrote several number ones, e.g. Carole King & Gerry Goffin, Burt Bacharach & Hal David. I'd have to compile any such list separately. The most successful songwriting team other than Lennon/McCartney (and possibly Jagger/Richards) was no doubt Jeff Barry & Ellie Greenwich (with Phil Spector sometimes added).