I remember Pete dissing Roger about his bad guitar playing in some fan magazine circa 1983.
Roger definitely knows how to play–was the lead guitarist in The Detours before Pete joined. Now, how good of a lead guitarist he was…well, skiffle bands of the day didn’t really require flashy players. His pre-gig warmup routine used to include strapping on a guitar and singing Johnny Cash songs:
No argument from me - he’s probably the single best example of a frontman who was totally carried by his bandmates. I’m pretty sure they had to literally carry him out there on more than one occasion, too.
I was going to say Ian Gillan of Deep Purple, but I checked and he played drums (and sang) in the very early days of his career, playing community centers and the like. He decided he couldn’t do both and switched to vocals only, for which we can be thankful.
If we count fictional bands, The Blues Brothers, of note in the movie of the same name, had Jake (Belushi), who showed no signs of using any instrument of any kind, and Elliot (Aykroyd) who only ever played harmonica.
I do wonder about the various boy bands. Did any of the New Kids on The Block, N’Sync, or others of that genre ever actually play any instruments?
Though they were “fictional” from the standpoint of the Jake and Elwood personas and backstory, they were certainly a “real” band, releasing two live albums, as well as the soundtrack album from the movie, before Belushi’s death.
Per post 11, vocal groups are not eligible for discussion in this thread. Boy bands (and girl groups such as Destiny’s Child) are disqualified. 
I think that’s an air bass guitar !
(looks like a rickenbacker)
Anyway, in play …
Johnny Rotten…
I did notice when watching it back on YouTube that it had been sweetened somewhat. In the live broadcast, Taylor flubbed the line “so casually cruel in the name of being honest”, pronouncing “casually cruel” as something more like “gradually gruel”. In the official YouTube video, which was posted ~3 hours after the performance, the line had been corrected.
I have no other comment!
Pentangle’s Jacqui McShee did not play any instrument.
Patti Santos of It’s a Beautiful Day only handled incidental percussion (tambourine, etc.)
Jane Relf of the original incarnation of Renaissance only did vocals. Same for Annie Halsam of the later version of the group (with occasional percussion).
Gary Puckett from the Union Gap doesn’t seem to have played an instrument.
Puckett’s biography says he played guitar.
I’ve seen bluesman Charlie Musselwhite in concert and he absolutely smashed it playing “only” harmonica. Then there was Sam Myers. Before he died in 2006 he toured with Anson Funderburg and the Rockets, doing vocals and harmonica.
Don’t sell the mouth harp short!
I’m pretty sure Kim Wilson of the Fabulous Thunderbirds is another one who only played harmonica along with vocals.
What a great band! I’ve seen them a bunch of times in a few iterations.
Agreed – harmonica definitely counts as an instrument!
I don’t know how much they really played (as opposed to relying on session musicians), but at least nominally, the Four Seasons were an instrumental band. See this clip, where all of them (except Frankie) are playing:
Thanks – ignorance fought!