In Impulse Tracker there was a nice template feature where you could copy a line of notes, and turn template mode on, and for each key you pressed it pasted the template in correct correlation to the note.
C4 E4 G4
Turn Template Mode On.
Template automatically enters
G4 B4 D5
It not only worked for 1 instrument but you could copy across mulitple instruments.
This feature is great for tracking chords, or even tracking in octaves, or single notes across multiple instruments.