| 1p4_zip | 1Password Backup Data |
| 1pe | Intuit TurboTax Form Data |
| 1pif | 1Password Interchange Format Data |
| 201 | StarMoney Agent Rollback Data |
| 2db | Cadwork 2D Backup Data |
| 2dm | SMS 2D Mesh Data |
| 2dp | GP Workbench 2DRadar Input Parameter File |
| 2dv | Cadwork Parametric Elements Data |
| 323 | H.323 IP Telephony Data |
| 32x | Sega 32X ROM Image |
| 330 | NCBridge XP330 Boot Image |
| 356 | IPC-D-356 Data |
| 3cn | 3D Movie Maker Scene Data |
| 3dc | CompuTrainer 3D Chart Screen |
| 3dc | iGO 3D Building Data |
| 3dcpack | 3D-Coat Extension Package |
| 3dd | Neuroscan 3D Coordinates Data |
| 3de | 3Data Expert Data |
| 3dh | SeisWorks Horizontal Time-slice Format File |
| 3di | Altair FEKO 3D Artwork Data |
| 3dmap | Catia 3DMAP File |
| 3dmap | Metaio SDK 3D Map |
| 3dmbak | Rhino 3D Model Backup |
| 3dmdef | 3DMark Definitions Data |
| 3dn | DreamPlan Home Design Software Model |
| 3don | Scrutinize 3D Mesh Data |
| 3dps | 3D eBook Shot Animation |
| 3dr | 3DMark Results Data |
| 3drep | Catia 3D Geometry Data |
| 3dtiles | Cesium 3D Tiles Database |
| 3dv | SeisWorks Vertical Time-slice Format File |
| 3dvs | 3DViewStation Document |
| 3dw | 3D World Studio Model |
| 3dweb | pCon.planner 3dWeb Data |
| 3dxmj | 3D-XplorMath-J Visualization Data |
