Fightificer [Ziegander, Fighter -- Martial Adept]
Summoner [T.G. Oskar, Summoner]
High Tier 3
These classes generally have much higher levels of power than average Tier 3 classes and may have a gamebreaker or two, but nothing that would bump them up to Tier 2.
Elocater [Jarian, Elocater, Psion (Nomad) -- Psionic]
Fighter Incarnate [Ernir, Fighter]
Monk [Jiriku, Monk]
Sorcerer and Wizard [Eldan, Sorcerer/Wizard -- Arcane, Non-Vancian]
Soulknife [Garryl, Soulknife -- Invoker, Psionic]
Spellthief [Jarian, Spellthief]
Ascetic [Jarian, Monk]
Duskblade, Psionic [Risada, Duskblade Variant]
Fighter [Lemmy, Fighter -- Pathfinder]
Jester [DonQuixote, Jester]
Marshal [PId6, Marshal -- Martial Adept]
Monk [lunar2, Monk]
Ninja [Circle of Life, Ninja -- Unique]
Open Palm [Veklim, Monk]
Quixotic Knight [DonQuixote, Knight]
Ranger, Retooled [T.G. Oskar, Ranger -- Divine, Vancian]
Rogue, Sublime [sirpercival, Rogue]
Shaman [Prime32, Shaman -- Binding]
Shugenja [Agent_0042, Shugenja]
Soulknife [Prime32, Soulknife]
Swift Hunter [Jiriku, Ranger, Scout -- Divine, Vancian]
Swashbuckler [PId6, Swashbuckler -- Martial Adept]
Swashbuckler, True [SneeR, Swashbuckler]
Village Priest [Dspeyer, Cleric -- Divine, Vancian]
Warlock, Retooled [T.G. Oskar, Warlock -- Arcane, Invoker]
Warmage, Retooled [T.G. Oskar, Warmage -- Arcane, Vancian]
Borderline Tier 3-4
High Tier 4 or Low Tier 3, either way they mean the same: classes that are just a little behind in either versatility or power to really make the Tier 3 cut, but standing above most Tier 4s, they could fall in either Tier depending on the level of optimization used.
Bard [DonQuixote, Bard -- Non-Arcane, Non-Vancian]
Bez-Kismet [T.G. Oskar, Hexblade -- Arcane, Vancian]
Daring Outlaw [Jiriku, Rogue, Swashbuckler]
Healer, Retooled [T.G. Oskar, Healer -- Divine, Vancian]
Marshal, Retooled [T.G. Oskar, Marshal]
Paladin, Retooled [T.G. Oskar, Paladin -- Divine, Vancian]
Soulknife [Risada, Soulknife]
Note that Tier 4 is not bad. Tier 4 is is, after all, "capable of doing one thing quite well, but often useless when encounters require other areas of expertise, or capable of doing many things to a reasonable degree of competance without truly shining." Many great classes are Tier 4.
Bard, Invoker [RedWarlock, Bard]
Fighter [Derjuin, Fighter]
Fighter [Wayfare, Fighter]
Hexblade [Semi-Official Fix]
Knight Champion [Person_Man, Fighter, Knight, Paladin, Samurai]
Monk [Amechra, Monk]
Monk Lite [T.G. Oskar, Monk]
Monk [UserShadow7989, Monk]
Ninja, Retooled [T.G. Oskar, Ninja]
Samurai [Ziegander, Samurai -- Psionic]
Samurai, Retooled [T.G. Oskar, Samurai]
Scoundrel [Circle of Life, Rogue, Swashbuckler]
Shadowcaster [Semi-Official Fix]
Warrior [Belial_the_Leveler, Fighter]
If your class is here, consider reworking it. Unless Tier 5 was your aim.
Samurai [Kazy, CW Samurai]
Pity the common man, for he is powerless.
Assume that you always need special permission to play one of these classes if I am DMing for you. This is because depending on your choices within the class, these classes can vary from Tier 5 all the way up to Tier 2 or even 1.
Healer [Quellian-dyrae, Healer]
Trissociate [JeminiZero, All Fix]
While mostly fitting the low Tier 4 end like the normal Healer, it is still better at healing than its original. What makes it Variable however, is the Rejuvenation option of the Rites, which make it more equal to a Tier 2 if there is a Tier 2 in the party. Plus teleport shenanigans possibilities from level 10 onwards.
This class highly depends on which Association you choose. Associations generally mimic already-existing official classes, so you can use the Tier of those classes to determine your Trissociate's Tier.