| adb | Intuit Quicken Address Book Data |
| adc | ABBYY Lingvo Custom Dictionary Data |
| adc | Active Desktop Calendar Dataset |
| adc | ActiveDocs Opus Clipping Catalog |
| adc | Chromeleon ADC Data |
| adc | ClearSight Analyzer Data |
| add | Advantage Main Data Dictionary |
| add | MapTek Vulcan Additional Structure Arcs Data |
| addism | Addism Data |
| adf | Act! Database File |
| adf | ReliaSoft ALTA Data |
| adg | Albatross Design Group 3D Scene |
| adh | Audible Download Helper File |
| adi | Advantage Database Server Index Data |
| adi | AutoCAD Device-Independent Binary Plotter File |
| adicht | ADInstruments LabChart Chart Data |
| adidat | ADInstruments LabChart Simple Data |
| adif | Amateur Data Interchange Format File |
| adiumhtmllog | Adium HTML Log |
| adiumlog | Adium Chat Log |
| adix | XML-based ADIF File |
| adj | ADS40 Orientation Adjustment Data |
| adj | BenMAP Adjustment Factor File |
| adj | FARSITE Adjustment Factors Data |
| adj | LISCAD Adjustment Control Data |
| adjusted | PLINK Basic Multiple-testing Corrections Data |
| adl | ADONIS Exported Data |
| adl | DESQview ADL Data |
| adl | openEHR Archetype Definition Language File |
| adm | Addict Dictionary |
