For the Shimano spindles, looking at the part number from the Shimano exploded views of the compatible pedals on Favero’s site and doing a cross-ref search at SJS Cycles, this is a listing of what pedals might make suitable conversion candidates (for the SHIMANO Favero spindles).
Favero Shimano spindles (l/r p/n) Compatibility based on lists from SJS Cycles
R7000** **YL8G98030 40
no others listed
**R550 Y43Z13100 Y43Z14100
- - Shimano SPD PD-M536
- - Shimano SLX SPD PD-M530
- - Shimano SPD PD-M515
- - Shimano SPD PD-M424
- Shimano Ultegra SPD-SL PD-6700
- Shimano Ultegra SPD-SL PD-6620
- Shimano Ultegra SPD-SL PD-6610
- Shimano 105 SPD-SL PD-5700
- Shimano 105 SPD-SL PD-5610
- Shimano 105 SPD-SL PD-5600
- - Shimano SPD PD-A530
- - Shimano SPD PD-A520
- - Shimano SPD/Flat PD-EH500
- - Shimano SPD PD-ED500
- - Shimano Click’R PD-MT50
- Shimano SPD-SL PD-RS500
- Shimano SPD-SL PD-R670
- Shimano SPD-SL PD-R550
- Shimano SPD-SL PD-R540
- - Shimano SPD-R PD-R535
- - Shimano Click’R/Flat PD-T421
- - Shimano Click’R PD-T420
- - Shimano Click’R PD-T400
R540 Y45F98020 30
Shimano SPD-SL PD-RS500
Shimano SPD-SL PD-R550
R8000 YL8B98050 60
Spindle can also be used on 6800 pedal
R6800 Y46N98070 80
No others listed
11/20/22: Additional known pedals to add to “will work”
PD M8000 (XT pedal)
PD A600 (SPD on one side), makes a nice light single SPD side gravel pedal with the SHI DUO spindles.
PD M959