I chose to use the Adonit Pixel/Pixel Pro with my 1st gen, 2015 iPad Pro.
If curious, here is my comprehensive, but incomplete list of Adonit Pixel compatible apps.
All apps listed support pressure sensing and palm rejection.
Animation Desk
Amaziograph
Adobe Photoshop Sketch ( palm rejection ONLY, No pressure sensing/line variations )
ArtRage
Art Studio Pro
AutoDesk SketchBook
Colored Pencil
Comic Draw
Concepts
Interactive SketchBook
Inkist
Medibang Paint
ProCreate ( palm rejection improved using special, non-electrical conducting, lycra-based material drawing glove )
Pixelmator ( used to support Adonit, I have an older version that did, not sure about their latest version )
Tayasui Sketches/Sketches Pro ( the new, free Tayasui Sketches School version works with this stylus, but without any palm rejection or pressure sensing, so you need to use a special, non-electrical conducting drawing glove with the Sketches School version to lay your hand/palm down on the iPad’s screen )
ZenBrush/Zen Brush 2
GoodNotes
Notability ( palm rejection noticeably improved using special, non-electrical conducting, lycra-based material drawing glove )
Note Shelf
Notes Plus
Notes Writer
QuickNotes X Pro
uPad
Zoom Notes
PDF Expert
PDF Pen
Foxit PDF