A few that I clearly remember: ctrl + shift + enter. This can't be bound separately from ctrl + enter (or just enter at all?), because shift enter doesn't lead to a "capital case enter".
Same goes for shift + enter.
So what I did was using a separate terminal emulator (alacritty) and mapping those to a key I wouldn't use, such as F12 o, for example. However figuring out the character code to bind f12 is also another business.
Again, I solved that, but binding shortcuts to me is possibly the most essential feature of a text editor and the operation was highly unpleasant.