cgCharacter
ACT is a complete suite of plugins to extend 3ds Max with advanced muscle and skin deformation tools for creating realistic character animations. Software overview, forum, tutorials, and downloads.

Creature Creator - FXRealm Studios
Creating humanoids, aliens, monsters, bugs, and other things that go bump in the night. Available high end plugin for 3D Studio MAX R2 and R3.

Cuneyt Ozdas
Offers users free and commercial software and plugins, Author of popular Texporter and ColorCorrect plugins

Double Duck Productions
Variety of architectural object plugins for MAX and Viz.

3dz
VirtScape utility that creates realistically looking landscapes. Free download.

Flatten - Mankua
Collapse all UVW Mapping channels to just one, and render all maps and textures, including 3D Maps, to just one bitmap.

HABWare
Custom 3DStudio MAX Plugins.

Havok
MAX Havok, real time dynamics plugin for 3D Studio MAX.

Kaldera Mankua
Bake full scene information into a single image for texturing an object. User's guide, tutorials, gallery, and product features.

Mankua Texture Layers
TexLay is an advanced parametric mapping and texturing for 3D Studio MAX.

MAX Plugins
A database of freeware plugins for 3D Studio: MAX R1.x/R2.x/R3.x/3ds MAX 4.

PolyTrans
Plugins for 3D Studio MAX providing dependable and seamless import and export of the most popular 3D file formats. It's a 3d model, scene, NURBS and animation translator.

PowerStamper : Mankua
A Texture Builder for 3D Studio Max by Bitmap Projection. This means that an image is projected onto the 3D surface of a model, and stamped into its material bitmap textures.

Size8 Software Inc.
Developer of Stitch a high quality cloth and clothing simulation plugin for 3D Studio Max 3.

Swift 3D
Windows standalone design tool that creates and exports 3D images and animation in a vector format. Exports to the Macromedia Flash format (SWF). By Electric Rain.

Tree Storm
A plugin for Max that enables the user to quickly populates the scene with photorealistic, 3D, parametric trees and vegetation and apply a wind motion. Comes with Tree Classic the tree creator, and expandable Tree libraries.