As the thread says. What are your banned/restricted races and classes? For the most part I allow any class or race into the game that was in the 3.5 PHB/PFRPG with the exception of the monk.
For 3.X
Banned Classes: Druid, Monk, Ranger, Barbarian, Paladin, all PrC's, any base class not in the PH unless excepted.
Allowed Non-Core Classes: Shaman (as Green Ronin wt. minor variations), Fanatic (Homebrew), Hunter (Homebrew), Champion (Homebrew), Explorer (Homebrew), Akashic (as Arcana Unearthed wt. minor variations), Feyborn (Homebrew)
There are however some differences between the homebrew fighters, wizards, clerics, rogues, sorcerers and so forth compared to stock 3.X. In general, most classes above tier 3 is now about one tier lower and anything below tier 3 is about 1 tier higher. The exact mechanics of that are too complex to go into.
Anything Else: Ask. The answer is probably "No" unless the concept is archetypal to fantasy and there is class in the above list capable of handing the concept, and you can't get there with multiclassing either. Keep in mind that I won't see a mechanical difference in how the class works as proof it can't handle the concept. For example, mechanics aside, a psion is just a sorcerer with a slight flavor change. If I wanted psions in my game, then I probably wouldn't have wizards and socerers and a wizard would just be a psion with a slight flavor change. If the only reason you want to play the class is mechanical, the answer is "No." If your whole character concept is mechanical, like, "I want full sneak attack and full BAB progression.", the answer is not only, "No.", but, "You might be unhappy with my table."
Banned Races: Halfling, Gnome, all races not in the PH unless excepted.
Allowed Non-Core Classes: Sidhe (Homebrew), Changling (Homebrew), Pixie (Homebrew), Goblin, Hobgoblin, Orine (Homebrew), Idreth (Homebrew)
Anything Else: Ask. The answer is probably, "No.", unless you have previously played one or more of the above previously and you have a darn good reason for wanting something unique and have enough understanding of the setting to understand the consequences of your choice. If the race isn't LA +0 and can't be made as LA +0, the answer will be no.
There are however some minor differences between the homebrew elves, goblins, hoblins, and so forth compared to stock 3.X.
Technically, I'm not sure that there is a race or class in my game that isn't 'homebrew', so in a real sense, everything published is banned.
Banned Alignments: None. However, everyone in the party has to be able to play with everyone else in a social manner. Anyone departing from party alignment 'norms', whether as a good guy or a bad guy (depending on the norm), has to take responsibility for finding a credible reason to be in the party and behaving in a constructive manner. This includes behaving in a way that another character is not provoked to consider you an enemy unless everyone is on board with intra-party conflict. In practice, there is no point in banning alignment. Most players aren't able to play more than one alignment, so 90% of all players play all their characters as the same alignment regardless of what's on the sheet. In practice, it works better to write on the sheet what they'll actually play than to try to fit the play into the alignment.