Brachygobius xanthozona (one of two species sold as 'bumblebee goby,' the other being Brachygobius nunus) can be kept with mollies in my experience.
Molly fry will be hunted relentlessly though, so if you intend to breed the mollies and want to save fry, I would not mix the two. For a small fish, they have BIG mouths, and if it might fit in the mouth, they will try to eat it. They did not bother adults at all.
They need a small 'territory' to call their own, and do not like it when other bumblebees invade. Provide lots of rocks, plants, other deco to break up their line of sight some.
Squabbles are common, but I've never seen a serious injury. Basicly a bunch of pushing and shoving and squaring off and 'daring' the other fish to come closer. Mostly just bluffing.
Cute fish, lots of personality, and fairly easy to breed too.