for vocals I use a lot of SoundToys stuff, the Decapitator or EchoBoy

This article on the making of Marr's 2018 Call the Comet album by MixOnline.com touches on some of the gear used during the recording process. "'“We used some Lexicon PCM91 outboard reverb and some EchoBoy, not necessarily timed to the track so it could bounce around a bit and fill space,' says [engineer] Doviak. 'I usually go for something slightly degraded, like a cheap Tape Echo--something with character that sits in the background, not distracting, but has some integrity. MicroShift Soundtoys is great for vocal doubling and widening effects. I’d often use Decapitator or Radiator for some dirt.'" (While the engineer is providing this feedback, the gear is housed in Marr's own Crazy Face studios, which contains gear he's collected over his decades in the music industry.)

In this video at 17:40 we can see Soundtoys Decapitator

at 6:20 in the video you can see the Decapitor in this breakdown of the track "Alone"

"Thank you @soundtoys for such great plugins."

He uses this in addition to Parallel Particles to make things sound beefier. Don't press the punish button.

In a livestream titled "Today's CoronaJam: A Hybrid Theory-style demo" on April 1, 2020, Mike Shinoda uses the Soundtoys Decapitator plugin. The session is available on the Shinoda Livestreams YouTube channel.

Used on Lamar's vocals for "All the Stars" as stated by producer Matt Schaeffer in this May 2018 Sound on Sound interview.

Kendrick Lamar’s vocal audio tracks, named after his teenage stage name K.Dot, consist of his first verse rap track, ‘VS 1 LD’, and 10 tracks for three moments in the track where he sings the pre-hook in a robotic voice. The verse rap track only has the AIR Flanger on it, and is sent to the ‘Dot VS LD’ aux track, which has eight inserts and five sends. Nine of the 10 pre-hook tracks have Auto?Tune, while the top four have a number of plug-ins on the inserts, including the EQ3 seven-band, Waves RVox, UAD Galaxy Tape Echo, SoundToys Little AlterBoy, SoundToys MicroShift and Valhalla Vintage Verb. These four are sent to a ‘Hook Ref’ aux track higher up in the session with another four plug-ins on the inserts and five sends. The other six are backing vocals to the four other pre-hook tracks and have no other plug-ins, other than a Trim, and are sent to a ‘Hook Background’ aux, just below them, which itself also is sent to the ‘Hoof Ref’ track. It’s a pretty complicated vocal signal chain, as Schaeffer admits.

“The ‘Dot VS LD’ aux indeed has a lot of stuff on it! I did most of the processing on that bus. On the inserts there are the SSL E-Channel, Waves RComp, Waves Q10 EQ, Waves DeEsser, UAD LA2A, UAD Pultec EQP1A, SoundToys Decapitator and Pro?Q2. The SSL channel strip, Q10 and RCompressor remain from the tracking, and maybe the DeEsser as well, but I most likely messed with the settings more during mixing. The Q10 has a high-pass at 50Hz and I notched out a frequency that was bothering me around 8.5kHz with the Q2. I added the other plug-ins during mixing, and they all add something a bit different. I’m boosting 100Hz and 16kHz with the EQP1A. As I said, I like using several EQs on one thing.

“The sends go to a ‘FlangeVerb’ track, on which I put the RVerb and the UAD MXR Flanger, then the ‘Huge Verb’ with the [Audio Ease] Altiverb and EQ3, ‘Hook Valhalla’ with the Vintage Verb, and the SoundToys EchoBoy, the ‘EMT250’ aux with the UAD EMT250, Valhalla Plate and MicroShift, and then finally a send to the ‘Dot VS Delay’ track, with the EchoBoy, set to quarter note, the Reel Tape Flanger and the RCompressor. The EchoBoy is the main delay you can hear in the verse. The EMT250 is not set to a reverb, but to a phaser effect, which gives a cool stereo effect. The Valhalla adds a bit of reverb here, though it’s set to -12, so it only gives a tiny bit of ambience, and the MicroShift makes the whole thing a little wider. It probably still sounded a bit dry, which is why I sent the track to the ‘Huge Verb’ aux with the Altiverb, again taking out low end with the EQ3.

“We use the Neumann M150 to record Tom’s vocals at the Clubhouse, because it has a tight pattern which diminishes the amount of bleed. You can see the verse lead vocal track, and immediately below it two vocal fix overdubs, because Tom changed a couple of lines, and below that the ‘Voc Amb’ track, which is the ambient mic that I always have set up close to Tom, pointed away from him. If I have to drop in a line, I can add some of the ambience that was on the original vocal mic. I also put that ambience at the beginning of the song before the vocal comes in. The verse vocal has a substantial effect on it, coming from the Decapitator, set on the ‘Old Radio Voice’ preset. Tom has this character in his lyrics, and he felt that it enhanced it to make it more lo-fi. It also meant that his voice sounds bigger in the choruses, when the effect disappears. The verse vocal goes through the 1176 and the MDW, with which I’m just rolling off some low end and adding at 8kHz.

“The chorus vocal is from the same live take, moved to a different track because I applied different processing. It also had the 1176 and MDW. I pushed a lot of 3kHz, to get it to cut through more. Tom sang the chorus part rather softly, because it fit his character, so it needed EQ to come out more in the track. All the vocal harmonies in the track were recorded at Tom’s place. Below the vocals there’s the ‘Vox slap delay’ aux track, which has the Digi Long Delay set at 150ms, and I ran it through the Decapitator, at the same setting as the snare drum.”

“…I love all the SoundToys plugins, I use a lot of Decapitator, Radiator, Devilok…”

can be seen at 21:05 in this video

Chorus lead vocal: Antares Auto–Tune EFX, FabFilter Pro–DS, Pro–Q2, Volcano, Pro–MB & Timeless 2, Waves Vocal Rider, Reel ADT, H–Delay & Doubler, UAD API 560, 1176, MXR Flanger & EP34, SoundToys Little Radiator, Decapitator & MicroShift, Audio Ease Altiverb.