No particularly good companies. They all get their memory chips from a small handful of suppliers. To make an effective product they have to adhere to pretty strict standards, so for all intents and purposes most memory is just fine.
If you wanted to get into overclocking and tweaking, then you want to track down specific batches of memory like Samsung DDR4 B-Dies (Not sure if there is much left out there, and I haven't been keeping track on what out there is good)
Corsair and G.Skill often make my recommendation lists, if only because they are generally price competitive for the most part and have decent looking memory.