Balaenas are in the Planar Handbook, as "elsewhales."
The only eladrin types so far unconverted are the shiere and noviere.
There are no unconverted archons or guardinals.
The noctral is very similar to the owl archon in the BoED. Not exactly the same, but close enough that they should at least be presented as related creatures.
Light aasimon and agathinons remain of the aasimon types.
Others still absent include the baku (although the shirokinukatsukami from OA is based on the same mythological creature), grim (1e MM2), dragon horse (1e MM2), buraq (Planes of Conflict, Al-Qadim MC), animal lord (PSMC1), animal warden (Planes of Conflict), per (PSMC1), zoveri (Planes of Law), busen (Planes of Law), t'uen-rin (PSMC2), foo creatures (PSMC1, although OA suggested they be treated as celestial dire lions or the like), kholiathra (MCA2), opinicus (MCA1), shard (Planes of Chaos, Tales From the Infinite Staircase), aeserpent (PSMC2), you mentioned the mortai (PSMCII), air maiden (1e Deities & Demigods), wraithworm (PSMC2), asrai (Planes of Chaos), incarnates (PSMC1, Dragon #193), forest wisps (Doors to the Unknown), mercurials (Doors to the Unknown), Arcadian pony (In the Cage: A Guide to Sigil), ethyks, and I'll have to look up some other more obscure things from Dragon Magazine.