Fall of 1965
The Highwaymen
https://en.wikipedia.org/wiki/The_Highwaymen_(folk_band)
The Righteous Brothers
https://en.wikipedia.org/wiki/The_Righteous_Brothers
Spring of 1966
Johnny Mathis
https://en.wikipedia.org/wiki/Johnny_Mathis
The Byrds
https://en.wikipedia.org/wiki/The_Byrds
The Mamas and the Papas