Big shout out to @johnmayergear on Instagram for pulling this information together. He's done a great job following the gear of this tour and I'll put together a single web page for all the information and where to buy some of the gear.
Additional information and pictures sourced from My Stupid Mouth John Mayer Gear - 2019 thread
Guitars: The rarities are the "all white" Silver Sky (paint, headstock, back of the neck) and the Silver Sky with maple fretboard. Most of the shows have been done with a Silver Sky. Silver Sky 'all white' Silver Sky w/maple fretboard ('New Light', mainly) Moc Sand Silver Sky The Black One ('Gravity') '64 strat Silver McCarty 594 ('Egde of Desire') 3-Humbucker Sunburst McCarty Charvel San Dimas ('Heartbreak Warfare') Duesenberg Double Cat ('Wildfire') Gibson L5 Martin D-45 Martin John Mayer D-45 Martin 00-45SC Martín OM-28JM 12-string National resonator There's more guitars on tour, but these are the one he has used so far. Pedals: Polytune 3 Keeley Katana Xotic Wah XW-1 Klon Centaur TS10 Mesa Boogie Flux-Five Boss OC-3 EHX Q-Tron+ Neunaber Slate Source Audio True Spring Strymon Flint Providence dly-83 Way Huge Aqua Puss Chase Bliss Audio Tonal Recall Keeley Katana Providence Chrono delay Neunaber Inmerse (not sure, he had it on the Asia tour) Some mini pedal JHS Kirkland boost There's a looper next to the tuner controlling a pedal that might be under the board. There's a Polytune mini noir next to the AquaPuss, that should be for acoustics. I'm missing a last pedal next to the dly-83, which I don't have idea what that is. There's a little pedalboard outside the floor monitors, has 3 pedals and one of those it's a Boss TU-3, so it might be something for the acoustics, but so far no clue on either the pedals or what are they for for sure. Amps * PRS J-MOD 100 * Two Rock John Mayer Signature The third amp has seen some changes. At first, it was the Dumble Steel String Singer #004, but for both MSG shows it was replaced with a Two Rock Sterling Signature, which is a clone of the very own #004. That amp was used heavily on the Continuum tour, also on 'Where the light is' and he played 'Continuum' in its entiriy on the second MSG show). The SSS #004was behind the amps, not being used. Cabs are J-MODs. A couple of 2x12's and a single 1x12, mic'ed with SM7B's. Behind the amps there are some Fender combos, including a Dual Professional