| ctpx | Microvellum Cut Parts File |
| ctr | BrainVoyager QX Contrast Data |
| ctr | CTRAN/W Define Format Data |
| cts | CrazyTalk Script |
| cts | GodswMobile Contacts Transfer Backup |
| ctt | ETCBC Coded Text Tabulated Data |
| ctt | LabVIEW Control Template |
| ctt | MSN Messenger Contact List |
| ctx | Cherrytree Password Protected SQLite Database |
| ctx | CTRAN/W Compressed Define Format Data |
| ctx | CyberTracker Exported Data |
| ctx | Forio Epicenter Model Context Data |
| ctx | Gasteiger Group CTX Chemical Data |
| ctx | Nokia PC Suite Contacts Backup |
| ctx | Pretty Good Privacy Cipher Text Data |
| cty | Fog Creek CityDesk Template Data |
| ctz | Cherrytree Password Protected Data |
| ctz | EFILive Calibration Tune Data |
| cu | 1C:Enterprise Configuration Update Data |
| cu | CU-SeeMe Data |
| cu | my Knowledge Explorer Change Unit |
| cu1 | PhotoLine 4 Curve Data |
| cu3 | PhotoLine 4 Curve Data |
| cub | Cubloc Studio PLC Data |
| cub | Gaussian Cube Data |
| cub | IBM Cognos PowerPlay Cube Data |
| cub | ISIS 2 Cube |
| cub | Microsoft Windows Installer Validation Module |
| cube | Gaussian Cube Data |
| cuce | CU-SeeMe Data |
