Plex is by far the best . And it can pull from a NAS too.
Too bad it does require a desktop computer, unless you have a smart NAS capable of running its ARM server. Unlike true UPnP apps recommended above; e.g., nPlayer.
Speaking of nPlayer, I've managed to fix its bug I've referred to above; see my just-posted article here at MR: https://forums.macrumors.com/threads/1569007/