Tutorials
Addons (in general)
Images
Making weapon HUD icons (by Doktor Haus on Steam L4D2 Guides)
Maps
Models
START HERE: Model Creation Overview (Overview of modelling for Source engine games on the VDC.)
Category:Modeling (Various links to modelling info and tutorials on the VDC. Includes links for help about many modeling packages.)
Compiling L4D2 First-Person Weapon Models (by arby26) READ THIS FIRST for view models.
IncludeModel Trick (by ZeqMacaw) READ THIS SECOND for view models because IncludeModel Trick is often needed.
L4D2 Weapon Compile Example (by arby26 - oldest mention of IncludeModel Trick that I could find)
Doktor's MDL Decompiling Tutorial (video by Doktor Haus)
Doktor's [Weapon] Model Swapping Tutorial (video by Doktor Haus)
Hexing [weapon] models in L4D2 (video by Funreal)
3dsMax Left 4 Dead 2 Survivor Creation tutorial (video playlist by SFM TURK)
Custom Melee Weapon (Valve Style) (by Splinks on Steam L4D2 Guides)
Custom Survivor Replacement (by Splinks on Steam L4D2 Guides)
Modding a Left 4 Dead 2 Survivor (by ZeqMacaw)
Convert a Survivor Mod to a Different Survivor (by ZeqMacaw)
Proportion Trick (Idea by CaptainBigButt; brief tutorial by ZeqMacaw)
Convert GMod ragdoll to player model & NPC + proportion trick (Video tutorial for Garry's Mod, but shows some useful techniques that can be applied to any Source-engine models. Shows the use of Crowbar, Blender, and Notepad++. Shows how to fix common problems of rotated head and thighs by simple editing of bones in Blender.
Converting model from SFM to Garry's Mod - start to finish [Blender] (YouTube video)
The complete guide to decompiling and recompiling models (It's on a TF2 forum, but the process is the same for L4D2.)
Blender 2.6 Manual - Starting section (Very useful for first-time users of Blender)
Blender 2.6 Tutorial 13 - Bones & Rigging 101 (Skips video to 10:21. The making of the armature/skeleton up to that time is not needed, because we would use the decompiled skeleton from the model we are replacing.)
TF2 Jigglebones Tutorial Using Blender (video; the process is same for L4D2 and for any 3D modelling tool)
Blender: Unwrap Tutorial... Nice and easy! (20 minute video about texture uv-unwrapping in Blender; WARNING: Some minor vulgar body-part word usage.)
Convert a Model to Left 4 Dead 2 Survivor (No longer updated; replaced by "Modding a Left 4 Dead 2 Survivor".)
(Blender) Rigging Source Engine Models to be Animated (first-person weapon rigging and animation) - Part 1, Part 2, Part 3, Part 4 (videos by arby26) NOTE: These videos teach how to rig specifically for making animations, *not* how to rig for replacing survivor mesh.
Blender 3D: Noob to Pro (On Wikibooks. Good overview of using Blender.)
How to Add Eye Posing to a Model (Described using 3ds Max, but applicable to any modelling tool.)
3ds Max Tips (Collected by ZeqMacaw.)
Practically any model to SFM via Blender (by Pte Jack on Steam Source Filmmaker Guides; includes example of using Crowbar to decompile a model.)
Procedural bones in Source Engine (and Source Filmmaker) (Forum topic started by revzin.)
How To: Posing Parameters on Source Models (by Jesse V92)
Tutorial: Porting GoldSource models to Source Engine using Crowbar for Dummies and Newbies (by loKkdoKk)
Importing Smoothing Groups into Blender (Idea and image by TFA; brief tutorial by ZeqMacaw)
Baking Vertex Animation Into SFM (Forum topic on Facepunch.)
Easily make shapekeys/flexes using the bones [Blender] (YouTube video)
Flex Making Quickie (YouTube video by Splinks)
Mutations
Custom Mutations Tutorial (by Rayman1103 on Steam L4D2 Guides)
Servers
Sounds
Bug-Free Custom Sounds (guide by Doktor Haus)
Bug-free sounds tutorial (video by Doktor Haus)
L4D2 Manual Sound Installation (by Doktor Haus)
Textures
Shaders for Source in Practice (by Noodum and 4ECHO)
VMT Parameter Reference (by Yogensia and Rafaël De Jongh)
Troubleshooting Missing Texture (by ZeqMacaw) MISSING TEXTURE? Seeing PINK and BLACK or PURPLE and BLACK CHECKERBOARD texture? Read this to solve the problem.
How to make Animated Textures (by Burnfingers on GameBanana)
How to make a Glowing Texture for Hammer with gimp (by Burnfingers on GameBanana)