Crimson Bat for sure. My second legendary troop after Sheggra, and one I loved for quite a while. I’ve been around long enough to remember when its health gain actually mattered.
The gowdb.com tool is funny for looking at troops I’ve never used by base rarity. A whole bunch of goose egg legendaries, and one mythic: Shade of Zorn. Just never even saw the point of trying him, I guess. 