Voadam
Legend
Formians (extraplanar colonizing ant person beings) are another classic LN monster, though there are those who consider that a problematic designation as they regularly take slaves and are not designated evil. WotC made them the big LN exemplar in 3e.
When the 1e MM came out it was mostly designed around the 5 point alignment system (Neutral, CE, LE, LG, CG as shown in the chart referenced earlier) so you do not see a bunch of CN or LN monsters in the core classic monsters but mostly in things that come later as AD&D moved to the 9 point alignment system.
Githzerai were originally Chaotic Neutral in the 1e FF but were able to be monks (who in 1e needed to be lawful) and their characterization as being in the Chaos of Limbo eventually flipped from the chaos plane as a natural fit to a characterization of their monk monasteries showing how their extreme lawfulness can be forged and tempered out of ultimate chaos and in 5e they are Lawful Neutral.
When the 1e MM came out it was mostly designed around the 5 point alignment system (Neutral, CE, LE, LG, CG as shown in the chart referenced earlier) so you do not see a bunch of CN or LN monsters in the core classic monsters but mostly in things that come later as AD&D moved to the 9 point alignment system.
Githzerai were originally Chaotic Neutral in the 1e FF but were able to be monks (who in 1e needed to be lawful) and their characterization as being in the Chaos of Limbo eventually flipped from the chaos plane as a natural fit to a characterization of their monk monasteries showing how their extreme lawfulness can be forged and tempered out of ultimate chaos and in 5e they are Lawful Neutral.