I've posted this in two formats. The first is by Year/Section. The second, the link to which is at the bottom, is all of files and sections at once. That's a big list.
Searching the list is simple. If you still have links to the old WOTC Boards, you'll find a 4 - 7 digit number in them. That's the thread number, and it's listed here.
If not, search for the title.

Still can't find it? Try the big list. If you can't find it there, it might be have been missed.
2005; Birthright
2005; Campaign Workshop
2005; Classes and Prestige Classes
2005; Core Colliesium
2005; D20 Design Anime
2005; D20 Design Character Development
2005; D20 Design Fantasy
2005; D20 Design General
2005; D20 Design Historical
2005; D20 Design Horror
2005; D20 Design Theoritical Optimization
2005; D20 Design Video Games
2005; Dark Sun
2005; Deities and the Planes
2005; DM Rules Counciling
2005; DND Adventures
2005; DND General
2005; DND Out of Print
2005; Dragonlance
2005; Eberron Classes Races and Monsters
2005; Eberron Combat Arms and Armor
2005; Eberron General
2005; Eberron Magic Dieties and Cosmology
2005; Eberron People and Places
2005; Eberron Xendrik Expeditions Xendrik Covenant of Light
2005; Eberron Xendrik Expeditions
2005; Epic Level
2005; Forgotten Realms Classes Races and Monsters
2005; Forgotten Realms Combat Arms and Armor
2005; Forgotten Realms General
2005; Forgotten Realms Magic Deities and Cosmos
2005; Forgotten Realms People and Places
2005; Forgotten Realms Realms FAQ
2005; Garics City
2005; Greyhawk
2005; Living Greyhawk Characters
2005; Living Greyhawk
2005; Magic and Spells
2005; Map of the Planes
2005; Monsters Lair
2005; Mystara
2005; Oriental Adventures
2005; OtherWorlds(Including3rdParty)
2005; Planescape
2005; Playing with Everything
2005; Prestige Classes
2005; Psionics
2005; Races
2005; Ravenloft
2005; Redgars Repository
2005; Skills and Feats
2005; Spelljammer
2005; The Guild House
2005; Whats a DM to DO
2005; Whats a Player to DO
2008; Campaign Setting; Dark Sun
2008; Campaign Setting; Greyhawk
2008; Campaign Setting; Mystara
2008; Campaign Workshop
2008; Classes and Prestige Classes
2008; Core Colliesium
2008; D20 Design - Anime
2008; D20 Design - Fantasy
2008; D20 Design - General
2008; D20 Design - Historical
2008; D20 Design - Horror
2008; D20 Design - Theoritical Optimization
2008; D20 Design - Video Games
2008; D20 Design Character Development
2008; D20 Design Character Optimization
2008; Deities and the Planes
2008; Dm Rules Counciling
2008; DND - Adventures
2008; DND - General
2008; DND - Out of Print
2008; Eberron Combat Arms and Armor
2008; Eberron General
2008; Eberron Magic Dieties and Cosmology
2008; Eberron People and Places
2008; Eberron; Xendrik Expeditions
2008; Eberron; Xendrik Expeditions; BlackWheel Company
2008; Eberron; Xendrik Expeditions; Cabal of Shadows
2008; Eberron; Xendrik Expeditions; Xendrik Covenant of Light
2008; Eberron; Xendrik Expeditions; Xendrik Crimson Codex
2008; Epic Level
2008; Equipment and Combat
2008; Forgotten Realms General
2008; Forgotten Realms Magic Deities and Cosmos
2008; Forgotten Realms; Classes Races and Monsters
2008; Forgotten Realms; Combat Arms and Armor
2008; Forgotten Realms; Living Forgotten Realms
2008; Forgotten Realms; People and Places
2008; LFR Adventures Discussion
2008; LFR Character Discussion
2008; Living Greyhawk
2008; Living Greyhawk; Characters
2008; Living Greyhawk; Rules
2008; Living Greyhawk Characters
2008; Magic and Spells
2008; Mark of Heroes
2008; Mark of Heroes
2008; Monsters Lair
2008; Non-DND TSR and WotC RPG Discussion
2008; Oriental Adventures
2008; Playing with Everything
2008; Prestige Classes
2008; Psionics
2008; Races
2008; Skills and Feats
2008; The Guild House
2008; The Guild House; Legend of the Guilds
2008; Unearthed ARcana and House Rules
2008; Whats a DM to DO
2008; Whats a Player to Do
2008; World Creation Project
2015; 4e Character Development
2015; 4e Character Optimization
2015; 4E Errata Archive
2015; 4e General Discussion
2015; 4e Rules QNA
2015; Campaign Setting; Birthright
2015; Campaign Setting; Mystara
2015; Community Business
2015; Core Coliseum
2015; Campaign Setting; DarkSun
2015; DND Adventurers League
2015; DND Future Releases
2015; DND Insider
2015; Campaign Setting; Dragonlance
2015; Dragon and Dungeon articles
2015; Dungeon Command
2015; Dungeon Master Help
2015; Eberron
2015; Forgotten Realms
2015; Gamma World
2015; Garics City
2015; Greyhawk
2015; Homebrew Settings
2015; Legends of the guilds
2015; LFR Adventures Discussion
2015; LFR Character Discussion
2015; Living Greyhawk Characters
2015; Living Greyhawk Rules
2015; Nentir Vale
2015; Non-DND TSR and WotC RPG Discussion
2015; Off-Topic Tavern
2015; Oriental Adventures
2015; Other Published Worlds
2015; Other Worlds (Including 3rd Party)
2015; Planescape
2015; Player Help
2015; Previous Edition Archieves
2015; Previous Edition Character Optimization
2015; Previous Edition General
2015; Print Material
2015; Product and General DND Discussions
2015; Ravenloft
2015; RPGA Conventions
2015; RPGA General
2015; RPGs General Discussion
2015; Rules Questions
2015; Spelljammer
2015; The Guild House
2015; The Map of the Planes
2015; Third Party and Officially Licensed Products
2015; Whats a DM to Do
2015; Whats a Player to Do
2015; World Creation Project


Please note, the E-mail Discussion Lists are not here, as they were not sorted by Topic, but by date. I sorted them that way to try to organize them.