We just introduced new cell shortcuts on Observable - see all of them in the Keyboard Shortcuts reference: https://observablehq.com/@observablehq/keyboard-shortcuts#cell
These add a bunch of keyboard-centric new abilities. You can navigate cells with j & k, select cells with x, delete multiple cells at the same time with Option-Delete, move cells with Shift Up/Down, pin or unpin multiple cells with Ctrl-Shift-P, and more. All of the commands that work with one cell in this mode work with multiple cells, making it pretty nifty for bigger notebooks.
These commands are a bit like vim’s normal & visual modes, and a bit like Jupyter’s command mode.