Mesh Online

Better Fbx Importer & Exporter adds FBX handling to Blender using the official FBX SDK. It imports FBX, DAE, OBJ, DXF and 3DS files, exports FBX, DAE, OBJ and DXF files, and is compatible with all FBX versions.

Voxel Heat Diffuse Skinning is a Blender add-on from Mesh Online that generates vertex weights for characters, including non-seamless meshes, by combining voxel heat diffuse skinning with Blender's built-in heat map diffuse skinning.

Corrective Smooth Baker is a Blender add-on from Mesh Online that bakes the Smooth Corrective modifier into vertex weights, so armature-deformed characters keep their smoothing after export to game engines.