A bit of a niche use case, but when using a physical (BlueTooth) keyboard on my phone with the note editor in the Android app (v3.4.7), the availability of common keyboard shortcuts like Control, Shift and/or Alt Left/Right is great, but Ctrl-Up and Ctrl-Down seem to be missing. Not that they don't modify the up/down key behavior, that holding control while hitting the up and down arrows doesn't move the cursor at all.
I'm not sure what the correct behavior would be, though at least keeping the normal up/down effect would be less jarring, Not sure if this is how it is in other text editors, but having ctrl up/down move the cursor by “paragraph” (that is, lines but not accounting for rendering word-wrap, only actual line breaks) makes sense to me. If so, I don't know if it makes more sense to maintain the visual position of the cursor or the number of characters (try going between a line of Ws and a line of Is to see what I mean). Whatever feels right coming from a desktop environment to a mobile one.
Having any keyboard shortcuts at all is super convenient in an Android app though, and I miss it in a lot of others, so thanks for that!