Mistwell
Crusty Old Meatwad
Legendary and Lair Actions can be used for ANY edition of D&D. Personally, I want to see a subclass of these evolve: Boss Actions, that can be used for low and mid-level monsters, not just high end beholders and dragons and such.
Oh yeah, those are good suggestions! For sure I can see Legendary and Lair actions being used in an OD&D game to good effect.