Except by "famous" we mean "obscure personal favorites over twenty years old"
And by "optimized" we mean often laughably limited one-trick ponies.
And by "character build" we mean one trick we slapped class levels to.
But this intro is too long already so on to the list.
Pun-Pun: sarrukh out of savage species can add/remove/set ability scores and any other special abilities. Using a +1 la template that grants 11th level wild shape and assume supernatural ability pun-pun takes advantage of this before most wizards cast polymorph.
The Omniscificer: by pretending there are no rules on how to stack effects you manifest several share pain powers so when you're dealt 8 damage you echo two 4 point totals to them whom in turn echo another two sets of 2 back to you causing you to echo two iterations of 1 damage back to them and OMG SQUIRREL! and that's how it's a none diminishing return and infinite then you just use masochism to gain a skill bonus based on damage received.
Jovocian Bomb: jovocs from the second monster manual have a super share pain effect that cannot self-target, by getting around that say by stealing the supernatural ability for a bit with a lot of bs, you can produce an actual working solution for the omniscificer's share pain loop with sadism.
The Terminator: a repost of the save game trick which is about psionic nomad that manifests time hop on a fission sending it into the future then the slave manifests a quickened divination to gain some intel and then use time regression to return to just before it's previous turn. Drastically outdone by using quintessence to send something into the heat death of the universe and forced dream streamlines the process.
The Wish & The Word: it just wishes for more wishes and observes that with a high enough caster level blasphemy can drive none-epic none-evil creatures just as equally as it can get a group of nuns to walk away from you.
Chicken Infested Commoner: The Maximum Hit Point Tank: it's another consumptive field like combo, this time necroincarnate's harvest soul heart of incarnum to gain a hit point for each of kill-fed essentia pool increase it obtains, runs a bajillion rounds slower than shapechange(shambling mound) & hitting your self with the electricity-based reserve feat.
The Jumplomancer: the exemplar can make a lot of skill checks using his diplomacy bonus, including escape artist, and so the someone decided it's best usage was jumping into people's rear ends.
The (Tauric) Hulking Hurler: this is what happens when your dm allows you to apply the same template six hundred times and then ignore the la because you think the tauric template's +4 is supposed to mean =4.
The Twice-Betrayer of Shar: it's a cleric of mystra that uses reach spell to modify touch spells into having a fixed range for persist spell and then overlooks how ocular spell doesn't change the range on the spell cast until after it's fired later.
Nanobots: 200 tiny creatures can share the same space and there are twenty six adjacent spaces next to you, now imagine what the aid other action can do for you.
Chuck E Cheese: by overlooking the fact that footsteps cannot be persisted you generate a large movement speed and use tornado throw to convert movement into damage as exactly as the maneuver tries to tell you to do.
The Emerald Legion: if mind flayers could craft custom magic items without xp costs and given free roam to apply templates they would probably copy Hitler's eugenics program with stuff like half-clay weredire air terrasquaes or something.
The d2 Crusader: pretends the luck domain's ability to set a result of '1' to a '2' actually alters the face that a die so the stance of chaos can deal infinite damage.
H.I.V.E: it's just a build that realized vermin lord lets you become lord of the flies as a sorcerer with a huge charisma score which is pretty much what it was expressly designed to do.
The Shepherd, The Saint, and the Sinner: it's just a build that realized D&D is a multiplayer game where a collective group of the standard four adventurers can share resources, so it used thrallherd to gain leadership instead of asking anyone to play because unnecessary convolution is a goal of optimization.
A bunch of random names: out of boredom someone asked if can you achieve a bunch of 100s for like two minutes a day and called it 100^10 because math was not their strong point. by casting a lot of spells/powers these builds probably, I mean no one actually reads them anyway, did it.
Cheater of Mystra: overlooks the fact that in a church of mystra a cleric gets free matamagic anyway to tell you how get a couple extra turn undead uses for divine metamagic with a minor tangent on how dweomerkeeper ignores material components.
The Lightning Thief: outdated rules text in the phb says you can steal stuff as a free action so just steal your self to move around because only a dm can limit your number of free actions per round and we never play with those.
A Full CoDzilla including a maximum turning pools option: it uses a dm provided artifact called the deck of many things, remember how we don't play with those, and assumes it produces exactly the cards you like by being a trick shuffler in real then throws the word cleric around for some bonus association.
The Basketweaver: the inspiration for this post, it just sits there making baskets as satire of all the I'm-special bs flying around.
The Dream of Metal: an actually very well made and flavored out post that for a brief moment salvaged GitP's reputation and explores what I said about the terminator.
True Dilettante: using embrace/shun the dark chaos and by reading any post listing where to obtain extra feats this thing gets extra feats.
"Festering Anger Lad": it's not even a build, more like someone's quote on a twenty year old "trick" called wand of lesser restoration and festering anger that decided you needed a bunch of class levels to pull it off.
Monty: how to become pun-pun by using plagiarism instead of manipulate form, aka first pass at updating outdated TO.
Tripple Cheesebuger with Onions: it's what happens if you don't read the ardent or southern magician entry, or your spellchecker, and want to achieve three different sources of 9th level casting without using an accelerated-casting class like the game wanted you to do.
Triple 9's: the above but lampshades cheese and uses accelerated-casting but still forgot illthid savant does the same thing without having a human claim he's a blind floating eyeball.
Bubs: optimized handle animal bonus can theoretically turn you into a pokemon trainer if they don't eat you.
New World Record Mount Familiar Companion by HD: I'm not even sure what this is supposed to be, pokemon ruby's rererelease?
Supermount v1, 2, 3, and so on: watch as people show off their breeds and attempt to win best in the show.
Sleeping Raven Infinite Blood Frenzy: look it's consumptive field again, only this time it's combined with the stance blood in the water because footnotes to a consumptive field suggestion list need to become a named build.
Clone Army: if body outside a body creates a fully stocked resource you can abuse then you can spend it's xp to cast wish.
Uberchargers: if you can't build one, you should read a list thread.
World Record for Rebuke: what happens if you read a list thread.
Maximum SA possible (per hit): what happens if you read a list thread.
Maximum Skirmish: what happens if you read a list thread that includes dragon mag.
Maximum Eldritch Blast Damage per hit: what happens if you read a.. just kidding. by illegally retroactively applying legacy champion and claiming la-buyoff applies to none-la levels you can gain an extra eight virtual levels of helfire warlock, except if only applies the bloodline benefit to hellfire and not the legacy champion levels even through it should either apply or not apply to both, forgets uncanny trickster and most other warlock builds deal more without even needing bloodlines or la-reduction.
The MAXED +1sorc casting non-ascended, Non-epic Demilich kobold: pretends you can buy off +8 la pre-epic and each time you buy off a point you are treated as being able to buy off the next one immediately as if you were say a +7er opposed to what the text does say and somehow only takes that logic as far as using the demilich template only rather than every template ever.
The Ultimate Bear Build: it's just a anthropomorphic black bear dire bear wildshaped bear druid / bear warrior with bear puns which is pretty unbearable. It's just a grizzly thread so be prebeared to bear with it.
Darkwing Duck: using wizard afcs it focuses on chaotic spells and with recall and shadowcraft mage so it casts and knows more than a sorcerer on top of getting new spell levels faster them the sorcerer too.
Sevenfold Dancer: sevenfold veil for spell immunity meets spelldancer for metamagics before facebook thought rainbows were cool, now google "ecdysiast" for me.
Paladin-Replacement: soro spends five paragraphs ranting about the paladin as he tries to tell you how great fist of raziel and ordained champion can be.
Risky: perfectly landed it's average damage in the range needed to incapacitate a balor at level 5 so it can be killed in a looney toon fashion to avoid the self-destruct.
Omnielemental: uses stormcaster's 5th level thunderbolt to stun and smite his opponents like an old testament god.
Eeyore: pale master with a schiver tortured soul is immune to damage caused by getting injured or losing your tail.
Summon Mirror Mephit's Rogue Deity: it turns out there is a 5hd deity printed in a web enhancement that would be a perfect candidate if you have simulacrum as a material-component ignoring sla.
Magikarp: you can ditch racial hit dice by failing your saves against energy drain effects, something something party support mumbling experience is a river and your 20th level is better than everyone else's.
Bestow Curse is a great buff: curse away a wilder's enervation, or everyone's memories of you to derail investigations, or how to always appear good to paladins, true dragons get epic spells, immunity to medusa's gaze by being unable to see her, calling everyone your friend and attempting to aid them results in a 50% no-save chance of failure, there are so many useful ways to curse your self.
Mirror Mirror On The Wall: it's not even a build, just a reminder that a mirror of opposition exists because the only thing that can beat pun-pun is four more pun-puns.
Jacky Chan: it's just a warforged warmage/warmage/war wizard/warweaver/warblade/warshaper that makes a man out of you like the bear warrior does but it's a lot harder to come up with puns for it.
Metalwork: an npc crafter than uses the aging curse to learn druid/cleric/bard/paladin/sorcerer spells through child of eberron, prestige bard, silver pyromancer, and rainbow servent as needed for magical items and custom runestaffs.
Cave Johnson's Monk: extrapolating unearthed arcane's possibility that class major variants can be treated as a new class, bloodline levels are applied to monk, sidewinder monk, chaotic monk, & wild monk for +50% more monk per monk.
Fumbles: it is a druid/rogue/fighter/monk/wizard/ranger/paladin/bard build with a splash of martial adapt/incarnate/binder/barbarian/spellthief/cleric/artificer/psion that delivers 5th level ranger/wizard spells and up to 9th level slas.
TL;DR: Lots of people posted some things.
More some day, maybe.