| awi | AIM Widget Package |
| aza | ProSystem fx Engagement Admin Package |
| azp | ProSystem fx Engagement Binder Package |
| b1 | B1 Compressed Archive |
| b6z | B6Zip Archive |
| ba | Scifer External Header Archive |
| balz | BALZ Compressed Archive |
| bbb | BlackBerry Mobile Phone Backup |
| bbtheme | phpBB Theme Package |
| bca | Jetico BCArchive Encrypted Archive |
| bcpio | Binary CPIO Archive |
| bee | BeeGui Bee Archiver Archive |
| bfa | Blowfish Advanced CS Encrypted File |
| bff | AIX Backup File Format |
| bh | BlakHole Archive |
| bhx | BinHex Encoded Archive |
| bkc | Backup4all Backup Catalog |
| bkf | Windows NT Backup Archive |
| bko | BackupOutlook Backup Archive |
| bkpi | Synology Hyper Backup Image |
| bks | Windows NT Backup Selection |
| bldl | BenchLink Data Logger 3 Package |
| bli | Blink Archive |
| bma | BMA Archiver Compressed Archive |
| bm_ | Compressed Microsoft BMP Image |
| bnh | BinHex Encoded Archive |
| bnhq | BinHex Encoded Archive |
| bny | Binary II Data |
| boa | BOA Constrictor Compressed Archive |
| boxer | Boxer for Mac Game Archive |