If you are a fan of Blender, you probably use a couple addons that have been developed to add extra settings or features in Blender. If you don't know about addons. Let me give you a rough background. Another awesome feature outside of being open source/free is that Blender provides its source code to developers of all backgrounds. This encourages the creation of a variety of addons. Most of these addons are free while others are paid. Here are my top 5 favorite free and paid Blender addons:
FREE BLENDER ADDONS
Archimesh, developed by Antonioya, is a very powerful Blender addon. It allows you to easily create architectural structures. One of my favorite features in this addon is the ability to choose from a variety of pre-built meshes: windows, doors, lamps, cabinets, columns and more! These pre-built meshes have simple settings built into them that allow you to easily customize each to your preference. Check out their demo video below to see how powerful this addon can be:
If you have Blender 2.5+ you should already have this addon. You'll just need to enable it in your user preferences. Sapling, developed by Andrew Hale, is an addon that allows you to create trees in a few simple clicks. Some of my favorite features include one-click presets for specific trees: Willow, Californian Black Oak, Quaking Aspen and Black Tupelo. It also allows you to create simple animations that simulate wind blowing through the branches.
Multi Object UV Editing
An addon developed by Andreas Esau allows you to UV map multiple separate objects at once, packing the resulting UV in one texture. This is a great addon that eases the process of creating UV maps for game assets and beyond. There is also a similar addon called TextureAtlas. I tend to work with the Multi Object UV addon, but try both and see which works best for you! Check out Andreas's demo below:
Blendermada - Blender Material Database
Although still in its Alpha stage of development, this addon is a very powerful addition to Blender's Cycles rendering system. The addon pulls from a library of pre-built materials that can be easily added to any project/mesh. One of my favorite aspects of this is that the material library is a collaborative effort from artists across the globe adding their own materials to the library. I'm really excited to see how the database grows. Check out the addon in action below:
The Blender community has been all a-buzz about Pixar's Renderman. Recently, Renderman has been in development for plug-in support with Blender. What's more exciting is you can take their alpha plug-in for a spin right now!
PAID BLENDER ADDONS
One of the newer addons on the market for $25. If you're looking for a simple to use easy tool that will generate landscape and nature work in Blender (terrain mesh, trees, etc.) then this is for you. This is a great tool for quickly generating natural landscapes for the Blender Game Engine.
This phenomenal $19 addon developed by Mike Pan focuses on the Blender game engine (Although it can be used outside the game engine for a variety of projects). Easy Game is a collection of tools that help you work quickly and efficiently with the Blender Game Engine. These tools include:
Easy Material: This tool allows you to quickly pop in normal maps, specular maps, emissive maps, etc. This is by far my favorite feature! The materials created are PBR compatible (AWESOME).
Easy Asset: This tool provides pre-built game assets that can be added to your scene at the click of a button.
Check out Easy Game in action:
The most expensive of the addons listed here, but worth every penny! At $71.25, this extremely powerful retopology tool enables you to retopologize your meshes with ease. Retopologizing a mesh is the process of rebuilding your model for use in a game or animation environment. This is the same process of simplifying a high poly mesh to a low poly mesh and then baking your normals, etc. See it in action below:
Gaffer Lighting Manager
A simple and easy to use $17.95 addon, developed by Greg Zaal, that helps you light your scenes. Gaffer presents you with all your lamp settings in one simple panel. Lighting environments can now be achieved quickly while maintaining realism. Check out Gaffer in action:
Developed by Cogumelo Softworks for Bake Rendering with Cycles and BI. This $14.95 addon optimizes your baking process in Blender. My favorite features include the multi-job and full scene baking functions. (Quick honorable mention: If you love BakeTool, check out MotionTool. This is another great addon by Cogumelo Softworks that uses a node based animation framework. This is a very powerful tool for motion graphic artists!) Check out BakeTool in action below:
Although these are my top 5 favorite free and paid blender addons there are TONS more. Interested in finding more addons? Check out the Blender Addon List on Blogspot for a complete list of FREE addons. I also encourage you to check out the Blender Market Addons. They have a nice list of high quality paid addons, most which donate a portion of their earnings to the Blender Foundation.