Private key insurance is one of the sectors I've been keeping a close eye on. Nunchuk Byzantine, AnchorWatch (recent SN AMA), LockedBTC, etc. leverage miniscripts for collaborative custody, inheritance planning, etc.
It's breaking down the Unchained's or Casa's of the bitcoin space into more independent advisory models, and clients still retain full control of their keys.
What Bitcoin companies or business models are you looking for that don't seem to be out there yet, or are just getting started?