My favorite slight of hand was that all the dungeons and caves were part of a single rectangular map. Designers carved out a few specific designs, then other levels were clearly what worked with the remaining map screens available so it all fit in the space they had, with caves thrown in to take up single screen gaps.

https://ian-albert.com/games/legend_of_zelda_maps/

And created them in somewhat recognizable shapes, e.g. eagle