Universal had a hit with Karloff in "The Mummy". oddly enough, it took them almost a decade to return to the wrapped horror, and then it was in a much lower budget. still, I saw all of these several times growing up, and it's like watching old friends. I know they are not the best monster movies, but they are very enjoyable.
here are the theatrical trailers for THE MUMMY'S HAND (1940), THE MUMMY'S TOMB (1942), THE MUMMY'S GHOST (1944) and THE MUMMY'S CURSE (1944). they are sort of interlinked in subtle ways, but nothing to try to figure out too much. each one of them has a cool scene or two to recommend it, but it would be almost twenty years until a truly scary mummy movie would be made.