Converting GLB to OBJ always preserves mesh geometry with normals, UV coordinates carried across. PBR materials, animation are dropped because OBJ cannot store them.
GLB is the binary form of glTF — a single file holding geometry, PBR materials, textures and animations. It is the default 3D format for the web, AR quick-look and most real-time engines.
glTF is the open 'JPEG of 3D' standard by the Khronos Group. The .gltf variant keeps JSON plus external .bin and texture files, which is handy when you want to inspect or hand-edit the scene description.
Wavefront OBJ is the oldest widely-shared mesh format: positions, normals, UVs in plain text, with materials in a companion .mtl file. Nearly every 3D tool ever made can read it.
STL carries triangles only — no color, no UVs, no scene. It is the lingua franca of 3D printing and CNC, where watertight geometry is all the machine needs.
PLY (Stanford polygon format) stores vertex clouds or meshes with arbitrary per-vertex properties such as color. It is common in scanning, point-cloud work and research pipelines.
FBX is Autodesk's interchange format, dominant in DCC pipelines (Maya, 3ds Max, Blender exports). It carries meshes, skeletons, animations and materials, but is proprietary and heavy.
GLB is the binary form of glTF — a single file holding geometry, PBR materials, textures and animations. It is the default 3D format for the web, AR quick-look and most real-time engines.
Wavefront OBJ is the oldest widely-shared mesh format: positions, normals, UVs in plain text, with materials in a companion .mtl file. Nearly every 3D tool ever made can read it.