Well, maybe Peter can tell us, but my Lumin application tells me that I have 399 MQA albums in Master and we all know that the real number is higher. If there was such a mark the Lumin application could make a "Select" of all the albums marked as MQA and that I know can not do it
Lumin app and Tidal desktop app show the human-edited Recommended Masters category (which shows only a small subset of all the Tidal MQA albums). In our account I see 458 album - I guess the difference in number may be due to regional licensing.
Both apps also show a MQA logo or M next to a music title - based on a tag for each track to identify whether it is MQA or not. So after searching for a particular artist, it is at least possible to browse and look for the MQA logo.
To my knowledge currently there is no way to automatically get the whole list of all Tidal MQA albums. Lumin app relies on the search functionality provided by Tidal, and searching for Masters is not currently possible. Merely having a tag is not sufficient for that (unless we scan each track one by one, but that's not a practical way.)