The A17 Pro (originally in the iPhone 15 Pro; now also in the iPad Mini) and A18 Pro (currently only in the iPhone 16 Pro) are the only chips Apple has produced

The A17 Pro (originally in the iPhone 15 Pro; now also in the iPad Mini) and A18 Pro (currently only in the iPhone 16 Pro) are the only chips Apple has produced with a "Pro" suffix. Apple used to use the X suffix for bigger versions of their phone processors that went into iPads (starting with the A5X); that went away when the M-series was introduced. And the "Pro" suffix itself doesn't seem to denote anything in particular-- there was never a non-Pro A17, and the "A17 Pro" going into the iPad Mini is itself a cut-down version of the chip that went into the iPhone 15 Pro (it has one GPU core disabled).