Im always amazed at reading these threads.. Im old.. so I played almost all the "odd" games in the arcade so they dont seem odd or obscure to me. Blueprint, this one I only seen one time ever... that mosnter chasing at top of screen was a nice touch, never cared for the game (But i never liked maze games much, even if my sig says so with my PacMan skills (long gone)) most of gems I see are non US released games like Guwange which was an amazing shooter. Dead Connection- kinda a slower paced Robotron with gangsters... and new backdrops (bar, junkyard, etc) one I never seen in arcades.
Some not so obscure but lesser known.
i always had a soft spot for the 2 shooters in 3 Wonders, some interesting fantasy work, very different. WARDEN- always a favorite of mine and one I could beat with a single quarter if I tried. And one I can temeber name of, you are a Robot fighting mosnters on several Planets... spiders, lizards etc.. very simple scrolling beat um up but I loved it when I played it. And gladiator... not so obscure but not a big hit. loved that game.