Queen, until it became obvious that Rockpera needs all the help it can get from no no synthesizers
Boston, because, um, true to the music, or something, so no instruments that had electrics, except electric guitars, but no synthesizers
Van Halen I,Van Halen II, until Eddie got his own 5150 studio and decided whatever shot he wasn't calling - no synthesizers , he now was, so no no synthesizersDreams
Yes: everything but no synthesizers, for a while
Emerson, Lake, and palmer no synthesizers - until their need to push the envelope included algorithmic faux mandolins.