There is the Rails-inspired web framework SML on Stilts: — https://github.com/j4cbo/stilts — presumably named after its great ergonomics.
And there is the SDL-powered MosGame, specifically for the Moscow ML compiler — https://github.com/Eckankar/MosGame — it comes with these examples: https://github.com/Eckankar/MosGame/tree/master/examples
But really, SML is primarily good for writing compilers.