We've got a bunch of questions in MTG around navigating the legend rule, and handling various cases involving legendary permanents in circumstances where the legend rule might apply. I've tagged them to aid discoverability (I'm sure I missed a bunch). I've called the tag mtg-legendary-cards and given it this description:
Questions about handling Legendary cards in light of the Legend Rule in Magic: the Gathering, and questions about the Legend Rule itself.
I feel this tag name may not be ideal as it might imply to people that any question involving a legendary card might warrant the tag. On the other hand I'm worried “legend rule” itself might be a relatively obscure piece of game terminology and thus [mtg-legend-rule] might or might not work.
What should this tag be called? Is mtg-legendary-cards fine? Should it be called [mtg-legend-rule] or something else instead?
In case you're wondering “why even tag this stuff at all? it's already tagged magic-the-gathering”, see Why the recent addition of MTG sub tags? for my reasoning. TL;DR: tagging is making it easier to find questions and duplicates in a topic than text search alone.