What are the names of some bands that opened for the Beatles on their 1964, '65, and '66 American tours?

Answer 1

Here's a list of some of the groups/solo artists (but not all), that opened for The Beatles then. The year each act appeared with them, is a little more difficult to find.

The Underbeats
Jay and the Americans
The Signs
The Del-Rays
Avi Vinocur
Cannibal and the Headhunters
The Remains
Jackie DeShannon
The Accents
Bobby Hebb
Lou Rawls
Kenny & the Kasuals
Brenda Holloway
King Curtis Band
Sounds Incorporated

Answer 2

It's not much, but I found out that when the Beatles played Shea Stadium in 1965, the opening acts were King Curtis, Brenda Holloway and Sounds Incorporated.