I've obtained all of the codex entries minus the ones below:

Alderaan - Paladin of House Organa - Titles
Balmorra - Hero of Gorinth Canyon - Titles
Belsavis - Master of the Burning Way - Titles
Belsavis - HK-51 - Persons of Note
Corellia - Liberator of Corellia - Titles
Corellia - The First Son - Persons of Note (Jedi Consular only)
Denova Novare Coast - Interrupted a Capture Attempt - Achievements: PvP
Hoth - Ice Wars Veteran - Titles
Nar Shaddaa - Scourge of the Underworld - Titles
Nar Shaddaa - Shadow Hunter - Titles
Quesh - Venom Drinker - Titles
Taris - Cathar Settlers - Organizations
Taris - Mandalorian Bane - Title
Tatooine - SIS Operative - Titles
Tython - Satele Shan - Persons of Note
Voss - Ambassador of the Republic - Titles

Some of them were granted to me after submitting a ticket. But as of right now, this is all I'm missing. According to the GM, the Titles have been removed from the game can can't be issued to me, regardless if I completed the content or not. They don't exist. So there ya have it. This is on my Consular.