This list contains all the info for asset types with its related tools & guides explaining the formats.

Type .Extension S1 Equivalent Info, Format, Decompiler
Animation vanim smd .smd files are added to a .vmdl through the Model Editor to make .vanim files.
Animation Sequence vgarp ? ??
Map vmap vmf Hammer Files.
No decompiler known to humans yet, but it is rumored that a magical penguin is working on it
Material vmat vmt Made with .tga files in the Material Editor.
Decompiler: S2DC
Model vmdl mdl Decompilation Guide: MDL to VMDL Conversion
Mesh vmesh smd,dmx,fbx Defines the shape of a model.
Loaded to the Model editor to make a new model.
Particle vpcf pcf Decompiler: S2DC
No method yet known for PCF to VPCF conversion.
Sound vsnd wav Takes wav/mp3 files and converts them to this file through a .vsndevts
Sound Event vsndevts txt Sound Editor reads the Source 1 strings which are identical to the ones used in Source 2.
Guide: Adding and playing Custom Sounds
Texture vtex vtx Compiled out of .tga files.
Compiler/Decompiler: ModKit
Guide: Extracting and Compiling VTEX files

It will be updated as we get more knowledge and build more tools for file decompiling and conversion.