| bldinp | OnScale Build Input Data |
| blend1 | Blender Document Backup |
| blend2 | Blender Document Backup |
| blf | CLFS BaseLog |
| blf | Common Log File System Binary Data |
| blf | MasterWorks Data |
| bli | Blaise Prepared Library |
| bli | LinkOne Library Data |
| blif | Berkeley Logic Interchange Format Data |
| blk | Abbyy FineReader Block Template |
| blk | Autodesk 3D Studio Max Block Library |
| blk | Autodesk AutoCAD Block Template |
| blk | Leica BLK360 Data |
| blk | Lightscape Block File |
| bll | ENVI Bad Lines List |
| blm | Envisioneer Catalog Data |
| blm | Rightmove Bulk Load Mass Data |
| bln | Golden Software Blanking |
| blo | IBM DB2 Binary Large Object Data |
| blob | IBM DB2 Binary Large Object Data |
| blob | Valve Steam Client Registry Data |
| blob | WOW! Diagnostic BLOB Data |
| blockplt | Lego Mindstorms NXT Block Palette Data |
| blr | Biacore BIAlite Project Data |
| blrb | Apple Extensions Manager Info Data |
| bls | Brush Lettering Saved Brush Style |
| blt | AOL Instant Messenger Buddy List File |
| bluebutton | VA Blue Button Data |
| bluestacks | BlueStacks App Player Data |
| blw | Adobe Photoshop Black and White Presets Data |
