>Rotom-A is the collective term for the Appliance Rotom Forms. So, Rotom-H, Rotom-C, Rotom-S, Rotom-W, and Rotom-F are all forms of Rotom-A.
>When it says that Rotom-A can counter Metagross (or "Rotom-A can do whatever"), it means that there is no specific Rotom form that needs to be used, as opposed to saying "Rotom-H can OHKO Forretress with Overheat", or "Rotom-C OHKOs Swampert with Leaf Storm".
Source: Marriland/ Rotom-A (Scroll to the bottom)
