oxygen lines

Some oxygen lines useful to astronomy:

• 557 nm green spectral line (recombination).
• 630 and 636 nm red lines (forbidden lines, [O I]).
• 500.7 nm green line ([O III]).

Also molecular oxygen (O2) lines:

• 686 nm absorption red line.
• 737 nm absorption red line.

(Like any chemical, possible lines produced by oxygen atoms and molecules are too many to count, but these are among those well-known for their usefulness.)