The late Max Sarmiento was greatly respected for his Cadena de Mano or Filipino Boxing skills. My original instructor Rene Latosa learned from him among others, and Rene has awesome empty handed skills. Nothing fancy, just very powerful and effective. Currently I'm working with the DTE system headed up by Maestro Martin Torres. He's another one with very fast, very powerful and very effective empty hand technique.
Not only does the empty hands component vary widely between FMAs, it also varies widely between practitioners within an art. I've had people tell me Balintawak contains no, some, or a lot of empty hands, for example. It's all over the place.