Ornaments
Adding grace notes
F4 N adds an acciaccatura at the cursor's pitch, or toggles acciaccatura/appoggiatura on a grace note you've already selected.
Adding slurs
A slur phrases together notes of different pitches, using the same select-then-shortcut spanner mechanic as hairpins and lines.
Glissando and tremolo
Both are set directly on a note, with no end point to pick — despite looking spanner-adjacent, neither glissando nor tremolo uses the select-start-then-navigate-to-end mechanic.
Trill lines and octave-shift lines
A trill line and an octave-shift line both use the same select-then-shortcut spanner mechanic as slurs and hairpins, stretching across a passage rather than sitting on one note.
Turns, mordents, and trills
Trill, mordent, turn, and their variants are a direct one-key toggle on a note — press a key, done, the same "no end point" mechanic as articulations.