There are some small modifications to the base classes on CD, such as adding more skill points or giving bonus feats. Modifications are italized.
All base classes have +2 skill points per level over default NWN.
Barbarian
Bard
Cleric
Druid
Favored Soul (Custom)
Fighter
Green Knight (Custom)
Monk
Paladin
Ranger
Rogue
Sorcerer
Swordmage (Custom)
Wizard
Warlock (Beta)
These classes have been modified, whether in the form of a name change, race restriction removal, adjustment from a single dragon color to any (RDD to DD), adding feats such as Assassins gaining Hide in Plain Sight at high level, prerequisites, or the adjustment of what levels class feats are gained at for WM/SD.
Arcane Archer
Assassin
Blackguard
Divine Champion
Dragon Disciple
Harper Agent
Knight Errant (Formerly Purple Dragon Knight)
Palemaster
Shadowdancer
Shifter
Weaponmaster
Unyielding Defender (Formerly Dwarven Defender)
Anointed Knight (Beta)
Arcane Trickster
Arcane Warrior
Archmage
Battlerager
Bladesinger
Deepwood Ambusher (Beta)
Demonic Servitor (Formerly Thrall of Graz’zt/Demonic Thrall)
Diabolic Disciple (Formerly Disciple of Mephistopheles)
Divine Disciple
Divine Seeker
Divine Trickster
Doomguide
Dragonsong Lyricist
Duelist
Eldritch Knight
Harper Mage
Harper Priest(ess)
Heartwarder
Heirophant
Hospitaler
Invisible Blade
Mystic Theurge
Red Wizard of Thay
Shadow Adept
Silverstar
Tempest
War Wizard
Windwalker