From the "Big Muff Users and Their Pedalboards" section of Kit Rae's Big Muff Page:

"Shown above: Jack White's NYC reissue Big Muff Pi Big Muff Pi (this first version was manufactured 2000-2001) from a November 2001 gig, with a Digitech Whammy-Wah. (...) His Digitech Whammy-Wah (later switched to a Digitech Whammy) was used for an octave-up effect. 'In my small pedal chain it’s the whammy first, then the Big Muff. What I like about the Whammy pedal is that it can raise my guitar an octave and what I like about the Big Muff is that it’s just distortion. I have them in that order because it’s not high-pitched distortion, but high pitch with distortion'"

Trent Reznor is confirmed to use the DigiTech XP-100 Whammy-Wah, as it is listed among the pedals in the Fragility Tour program, which details the equipment used to record "The Fragile." This information is sourced from nin.wiki’s page on "The Fragile (halo)."

Brian Welch's guitar tech mentions his DigiTech XP-100 at 16:16, in this rig rundown video, and it can be seen on Welch's pedalboard. This pedal is also mentioned in the 2020 Premier Guitar interview.

Another of Scofield’s pedals, the Digitech Whammy-Wah is his, “favorite of the DigiTech ones,” (6:23). “Most people like the other whammy pedal I like this one,” he says. “I don't know. It's kind of a lot of different effects. The way I have is set up right now it's six presets I have a set for a couple of wahs that I use occasionally. The second is auto wah I use that a lot if you like that auto wah thing…I have a [pre]set so I can whammy down the whole set. That's kind of a whammy bar effect, but on the pedal. And then I use this preset which brings it up one octave. Then I have a [pre]set to go up two octaves if I want for some really ‘out’ type effect. And then this last preset that I have it's set so it's octave below, and the original note - like an octaver thing. That's kind of whammy bar effect but on the pedal…”

"The first thing we go through is the XP-100, and I have a gain control on the back of that so if anybody's looking at all these pedals thinking 'You're gonna lose a lot of signal', you can get it back by just turning up the volume on the XP100." – Jim Otell (Munky's guitar tech) on the DigiTech XP-100 Whammy-Wah.

This pedal is also mentioned in the 2020 Premier Guitar interview.

Our go-to’s are the XP-100 [Whammy] from DigiTech and an old Ibanez chorus pedal.

You can see it in his pedal drawer at 7:03

at around 16.35 in this video you can clearly see it

Here you can see Clint's pedalboard during Sevendust's set at Woodstock '99, among other pedals he is using a Digitech XP-100 Whammy-Wah.

"His guitar rig includes a DigiTech 2120 and Whammy Wah and a Piercing Moose octave distortion pedal by Way Huge Electronics. A Ground Control MIDI Switcher keeps all this in order."

En este reel de Instagram durante un ensayo para el día de la música Chilena se ve que en una de sus pedalboards usa un XP100.

"The Whammy Wah is like an old 90s pedal. I bought a couple of these because they keep breaking; I think they're just made for the studio, really, [...] the whammy effect is something that I use an awful lot just for texture and when [I'm] using a lot of delay and other stuff and it sounds really tasty. It's got some other stuff on there like auto-wahs and filters and stuff like that."

In this photo from Bora Karaca's Instagram, it shows a few pedals in his studio. Among these is the DigiTech XP-100 Whammy-Wah.