From Unify Community Wiki
- Tip of the day - User-provided tip of the day.
- Special Folder Names in your Assets Folder - Some names for folders have special properties in Unity.
- Maximize Unity Game in Windows - C# .unity3d wrapper window that can be maximized, dynamically resized, and remembers state.
- Moving and Copying Unity Assets - Don't use the Finder!
- Customized Packaging - How to customize the Unity packaging process, which occurs after a build.
- Font Creation - An Adobe Illustrator template file to help create font textures.
- VRAM tips - Chart of texture compression sizes in VRAM
- Creating Screen Savers - Use the unity web player to create Unity screen savers.
- General Performance Tips - These guidelines provide a ballpark for making a decently performing game with Unity.
- Adjusting light levels - How to calibrate your monitor and adjust textures and lighting to have good gamma.
- GUISkin Creation Walkthru - Creating GUI Skins - From Illustrator to Photoshop to Unity.
- Use non-English fonts with GUIStyle - How to make international characters appear in your UnityGUI display.
- Array Editing - Undocumented features that make editing arrays in the editor less painful.
- Two Instances of Unity3d - Want to open two Instances of Unity3d? Here's how.
- Xbox360Controller - Xbox 360 Controller button references.
- LogitechController - Logitech Controller button references.
- Known Issues - List of known issues in Unity itself.
- Https WebPlayer - How to set up webplayer to work with https.
- Beginner's Scripting Guide - The basics, to help those new to programming.
- Event Execution Order - The order in which events in your scripts are called by Unity.
- Which Kind Of Array Or Collection Should I Use? - Choose from Unity's Arrays, .NET's Arrays, ArrayList, Hashtable, List<> and others.
- RGB values via script - How to get the perfect color values using script.
- Common Scripting Pitfalls - We've all been there. Here's the place to learn so you don't go there frequently.
- Unity's Ambient Lighting Algorithm - Describes how to calculate the color of a pixel of an object that's subject to lamp and ambient lighting.
- Converting Between Coordinate Systems - finding one object's position relative to another.
- C Sharp to Boo - Syntax differences between Boo and C#.
- Quick Editor - Generate Hashes - An example on how to create a quick editor script to generate MD5 Hashes on a list of game objects
- Editor Scripting Detailed Overview - A detailed look at editor scripting, useful for people who want to write more complex in-editor tools
Text Editors and Development Tools
- Script Editors - Overview and comparison of script editors for use with Unity.
- Playing Your Game From A Text Editor - An AppleScript which starts your Unity game from within your text editor.
- Syntax coloring for Boo in Unitron - plists for Smultron to add Boo syntac highlighting and function finding.
- Setting up Visual Studio for Unity - All you need to know to set up a smooth workflow for C# development for Unity.
- Setting up Visual Studio for Unity on Mac - If you like to combine the both of best worlds and run Unity on the Mac but Visual Studio on a virtual machine running on that Mac (VMWare Fusion or Parallels), this will provide you some valuable information and solutions to common problems.
- Manual Compilation of C# Unity Scripts - How to compile C# Unity scripts on the command line, to ease integration with editors such as Vim.
- Using Dreamweaver as a script editor - A quick tip to help with using Dreamweavers expand/collapse features - good for longer scripts.
- Fix Function Popup Menu in Unitron - Fix for Unitron to show public, protected and private scoped UnityScript functions in the pop-up function menu.
- Using Notepad Plus Plus as a script editor - Directions for replacing UniSciTE with Notepad++
- 3D Applications - Which 3D applications are compatible with Unity.
- Animeeple - Using Animeeple with Unity.
- Blender - Using Blender with Unity.
Additional Blender plugins/tools
- Make human - 
- MakeHuman Make Walk - 
- Archimesh - 
- Procedural city Generation - 
- Chromely's Ruler 
- Carrara - Using Carrara with Unity.
- Cheetah3D - Using Cheetah with Unity.
- Cinema 4D - Using Maxon's Cinema 4D with Unity.
- dim3 Inspire - Using dim3 Inspire with Unity.
- Lightwave - Using Newtek's Lightwave with Unity.
- Maya - Using Autodesk's Maya with Unity.
- Modo - Using Luxology's Modo with Unity.
- MotionBuilder - Using Autodesk's MotionBuilder with Unity.
- SketchUp - Using Google SketchUp with Unity.
- Wings3D - Using Wings3D with Unity.
- 3D Studio Max - Using Autodesk's 3D Studio Max with Unity.
- Softimage XSI - Using Softimage XSI with Unity.
- Free 3D Models - Websites containing free 3d models.
- Commercial 3D Models - Websites containing commercial models.
- Free Animations - Websites containing free animations.
2D Tools and Resources
- Photoshop - Using Adobe Photoshop for creating textures and user interfaces.
- GIMP - Using Gimp for creating textures, sprites, and UI
- Free Textures - Websites with free textures, backgrounds and photography.
- Commercial Textures - Websites with commercial textures, backgrounds and photography.
- Audio Applications - Audio applications and their compatibility with Unity.
- Unity 3D Obfuscator - Tool to protect Unity3D applications from decompilation
- Debugging and Profiling with Unity - How to eliminate bugs and measure performance
- Reflector - A C# program to dump an assembly classes, methods, and attributes, command line usage
- PrefabScriptableObjects - An example of how to keep some fancy data in a ScriptableObject serialized as a prefab
- General OpenGL Resources - Links to relevant background information on OpenGL.
- Minimum Graphic Card Requirements - What Unity features are supported by what levels of graphics cards
Tips to reduce head scratching while developing for the iPhone.
- iOS Video Tutorials - Free video walkthrough of how to set up a developer account, use the Unity Remote, and provision your device for development and app store submission.
- Unity iPhone Problems and Solutions
- iPhone Optimization Tips
- Smultron (Unitron) Unity Keywords (OBSOLETE by Unity 1.6) - Highlight and Autocomplete your Unity script.