The Reel Tape Saturation was used on Grohl's intro vocals for "The Pretender", as stated by mix engineer Rich Costey in this March 2008 Sound on Sound interview. An image of the settings can be found here.

Very few plug-ins were used on the mix for 'The Pretender', but intro vocals were treated to Reel Tape Saturation and Pultec EQP1A, while a vocal overdub at the end of the track was processed with Sound Toys' Echoboy.

(...) Vocals: Mercury EQH, UA 175, Roger Mayer RM58, Waves DeEsser, Digidesign Reel Tape Saturation, Sound Toys Echoboy, Pultec EQP1A, SPL De-esser, Neve Portico 5042

"If I recall correctly, the lead vocal is doubled throughout the song. I used a Waves DeEsser plug-in on it, which I'm quite a fan of, as I've not heard a hardware de-esser that is competitive with it. The main signal chain after that was a Mercury EQH tube EQ and then a couple of vintage UA 175s. I hit the background vocals with the Roger Mayer RM58. I haven't mentioned any plug-ins yet, apart from the Waves DeEsser, because I hardly used them on 'The Pretender.' The only other ones I used were the Reel Tape Saturation and the Pultec EQP1A on the intro vocals, and the Sound Toys Echoboy on one of the end vocal overdubs.

"I used board EQ on all the vocals. The Pultec EQP1A plug-in on the intro vocals was to help them cut through. The Reel Tape Saturation was a plug-in that I had just bought. I wanted to warm the vocals up a little bit with it and make them a little bit crisper. Nothing too distorted. The Echoboy plug-in was used on a vocal overdub at the end for a tight delay. I don't tend to use plug-ins that much; they're really not that interesting, in my opinion. Finally, I also used an SPL De-esser on some vocals, and the Neve Designs Portico 5042 for a bit of crispness. It has its own sound, and I used it a lot on the whole Foo Fighters album.

"To complete the picture, I used an EMT plate and the room mics for general reverb, and my two EAR 660 limiters were my bus compressors, together with the Manley Massive Passive. We printed the mix to the ATR102, on half-inch analogue tape, from which it was mastered."

The Reel Tape Flanger was 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.