Kurt Cobain used duct tape to cover the circuitry of his Jaguar guitar and as a makeshift strap button on his Vandalism Strat during the Paramount show. He was also known to cover the logo on his Marshall cabinet with it. This usage is referenced in an image on Pinterest by cristina.

Billie Joe Armstrong uses duct tape instead of strap locks to secure the strap on his iconic "Blue" guitar. This is evident in a photo from 1994, showing the tape wrapped around the strap.

Tom Morello uses Duck Tape on the strap of his "Arm The Homeless" guitar, as seen in the full concert video of Rage Against The Machine at the Aragon Ballroom in Chicago on September 16, 1996, provided by 7thLvl on YouTube.

Around the timestamp of 20:36, Lee shows the Harmony Bobkat that belonged to Thurston with a lot of duct tape, many Guitars from Thurston had duct tape

at the timestamp 1:32, Mike Dirnt's microphone can be seen held to the stand with what appears to be a piece of orange duct tape

Wes Borland used Duck Tape as a strap holder during the early days of Limp Bizkit, as evidenced by the image provided.

Jeff Buckley used Duck Tape as a strap holder on his Rickenbacker guitar, as evidenced by the image provided.

at the time stamp, 1:24 Tre can be seen with duct tape on the heads of some of his drums

Brian Welch used Duck Tape as a strap holder in the 90s, as evidenced by the image provided.

Reginald "Fieldy" Arvizu used Duck Tape as a strap holder in the early days of Korn, as evidenced by the image available on Equipboard.

"This is just used to keep the strap from falling off. At our first gig, the guitar strap kept losing hold when I would adjust pedal settings on the floor and I had no strap locks at hand, so I went to a nearby store and bought some duct tape to keep it in place just for the night. It worked quite well and has done ever since, so I’ve never felt the need to upgrade to the popular Grolsch bottle washers or even strap locks themselves."

https://guitar.com/features/interviews/black-midi/

James "Munky" Shaffer's original Ibanez Universe guitar from the 1990s is completely covered in Duck Tape, as evidenced by a photograph from a studio session in Los Angeles in 1999.