Back in the early 80's James Hetfield used a modified Marshall JMP 2203 (the amp which later became the JCM800 2203) he used this amplifier up until 1984 because it got stolen. After the amp got stolen, James bought a JCM800 2203 and had it modified.
These amplifiers can be seen on a lot of live footage of the early Metallica days as well as on the documentary "Some Kind Of Monster" You cab see the amplifier in this picture as well. https://www.flickr.com/photos/dyingindowney/2432208001

at about 13:25 into the submitted video, Kirk can be seen playing a Marshall JMP, and i know Kirk loves his vintage Marshalls.

In this video for Premier Guitar, at 2:28 Brent talks about his amps - "I'm running two Marshall JMPs and a '98 Diezel VH4"

When asked what amps he used in the studio: "A ‘68 Marshall Plexi Super Lead panned on one side of the stereo field and a Marshall JMP panned on the other side. Believe it or not, this was the first time I had ever played through a Marshall amp. I played both of them simultaneously through a Framptone Amp switcher with my signature Ibanez AT300 and AT100 guitars, which enabled me to play both amps with one guitar loud and clean using a tape echo and tube driver in front. For the album’s title track, I re-amped the Marshall through a Leslie 122 cabinet to get that swirling, Hendrix-y sound."

Paul leaning against his Marshall JMP Superlead 100 Watt stack.

"I use the same Marshall amp I’ve always had, a 1978 Super Lead 100 with a modified preamp by Dave Friedman. I came to him with this other amp that I liked the sound of, and we used that as the preamp." – Billy Howerdel on his 1978 Marshall Super Lead 100

Mentioned as a part of the rig used to record his debut solo album, "What Normal Was", according to November 2022 Guitar World interview.

There’s the Gibson Custom Classic given to him by Trent Reznor in the mid Nineties, his Dave Friedman-modded 1978 Marshall Super Lead, the Gibson Goldtone he describes as a “pirate sound” — and that prized Experience octave fuzz by Prescription Electronics. “The Marshall mod was mainly to do with the power tubes and biasing,” Howerdel says. “It’s a fast amp that reacts instantly, which there are pros and cons to... It has a different sound to your typical softly overdriven Plexi head. I found this 60-watt Naylor combo and loved it, so I showed Dave Friedman and he modded the Marshall to sound like that. I don’t even know if they still make those Experience pedals, but they’re hand-painted in different colors and sound great. I enjoy using the Fractal octaver too, rolling the volume down with the tone completely off to get this ghostly thing that, again, doesn’t sound like guitar, but maybe that’s why I like it!”

In a video titled "Jimmy Eat World: Our Career Through Music Gear" by Reverb on YouTube, Jim Adkins states that he recorded every album from "Clarity" onward with his 1979 Marshall JMP Superlead 100 Watt. He also mentions that he toured with this amp, along with a matching 4x12 cab, from the "Clarity" album up through "Chase This Light," before switching to his Vox AC30 Custom Classic.

According to this Guitar Geek rig diagram, Vincent Accardi used a 100 watt Marshall JMP head (likely the 100W superlead).

Wolf Hoffmann used the Marshall JMP Superlead 100 Watt amplifier during the 1980s, as detailed on his website in the "Behind the Scenes" section.

From live at Dynamo in 1983, Michael uses a Marshall JMP throught the concert

You can see the Head right behind him

Kee used 3 Marshall JMP Superlead 100w modified by Tommy Folkesson