| ard | ArtiosCAD Workspace |
| arescol | Ares Galaxy Collection List |
| arexport | Spark AR Studio Export Data |
| arf | AOL Instant Messenger Resource Data |
| arf | FITS Auxiliary Response Data |
| arf | WebEx Advanced Recording |
| arff | Weka Attribute-Relation File Format |
| arfx | Spark AR Studio Effect Data |
| arg | Autodesk AutoCAD User Profile |
| arh | ArHymo Hydrologic Simulation Data |
| arlnk | Ares Galaxy Link Data |
| arlold | AOL Organizer Backup Data |
| arm | Alphacam Router Param Macro |
| arm | Armadillo Protected File |
| arm | ArmorPaint Asset Data |
| arm | MySQL Archive Storage Engine Metadata |
| armodel | Kudan AR Model |
| aro | Autodesk Simulation Mechanical Reaction Force Output |
| arp | Adobe Audition Replay Data |
| arp | Alphacam Router Post Data |
| arp | AMS REALTIME Data |
| arpack | ArtRage Package File |
| arpatch | Spark AR Studio Patch Data |
| arr | Cubase VST Arrangement Data |
| arr | Multimedia Fusion Array Data |
| ars | Adobe After Effects Render Settings |
| ars | Artifax Event Report Editor Data |
| ars | Corel WordPerfect Office Audio Data |
| arscript | ArtRage Script File |
| art | Alphacam Router Tool Data |
