| ndb | Act! Notes Database |
| ndb | ClamAV Extended Signature Data |
| ndb | NEPLAN Network Node Data |
| ndc | Nick-O-Matic Design Factory Data |
| ndd | Nikon Capture Dynamic Exposure Extender |
| ndf | Channel Data File |
| ndf | Microsoft SQL Server Secondary Database File |
| ndf | NeoPlanet Browser Data |
| ndf | NimbleGen Design Data |
| ndi | Novell Netware Device Information File |
| ndj | Newline Delimited JSON Data |
| ndjson | Newline Delimited JSON Data |
| ndk | Lotus Notes Design Elements |
| ndl | Lotus Notes Data Link |
| ndl | Nick-O-Matic Design Factory NDL Data |
| ndm | Navicat for MySQL DataModels Data |
| ndots | Ribbons Polygon Definition |
| ndp | NET Deed Plotter File |
| ndpa | Hamamatsu NanoZoomer Annotation Data |
| ndpr | Hamamatsu NanoZoomer Digital Pathology Image Format Data |
| ndpvs | Hamamatsu NanoZoomer Script |
| ndr | Nikon Capture Image Dust Off File |
| ndr | Rave Reports Report Data |
| nds | Nero Burning ROM DiscSpan Compilation |
| nds | Nick-O-Matic Design Factory NDS Data |
| nds | Nintendo DS ROM Image |
| ndt | NEPLAN External Program Data |
| ndt | Niton Data Transfer File |
| ndu | SymbianOS Backup Data |
| ndv | ENVI N-D Visualizer State Data |
