| aor | Searchlight AR3000 Radio Scanner Frequency Listing Data |
| aorder | FotoMagica Data |
| aot | Novell Application Object Template |
| ZENworks snAppShot Application Binary Object Template |
| aov | ASReml ANOVA Calculations Data |
| ap | ArtPro Plus Data |
| Entrypoint 90 Application |
| ap11 | Siemens TIA V11 File |
| ap2 | ActivPrimary Resource |
| ap5 | Koyo Screen Creator 5 Transmission File |
| apa | RSView Application Manager Archive |
| apalbum | Apple Aperture Album |
| apb | Alphacam Punch VB Macro |
| LonWorks Binary Neuron Application Image File |
| apc | AiroPeek Wireless Trace Capture |
| Arcplan Enterprise Connection Data |
| apd | Adobe PageMaker Printer Description |
| apdb | Apple Photos Database |
| apdetected | Apple iPhoto Detected Faces Data |
| apdisk | Mac OS X Disk Information File |
| apdv | Analyte Point Data File Format Data |
| apertureedit | Apple Aperture Edit Data |
| apf | Adobe Profile Format File |
| ATO Profile Data |
| Autodesk Showcase Packet File |
| apfacename | Apple iPhoto Face Data |
| apfolder | Apple Photos Folder Data |
| apg | PowerADA APG File |
| aph | Ability Photoalbum Album Data |
| api | Adobe Acrobat Plug-in |
| Adobe Photoshop Ink Colors Setup |
| apin | Adobe InDesign Filter |
| apk | GameSpy Arcade Service Data |
| apkg | Anki Exported Flashcard Deck |
| apl | Arcplan Enterprise Object Library |
| aplibrary | Apple Aperture Library |
| aplmodel | iCal Application Layout Data |
| apm | Alphacam Punch Param Macro |
| apmaster | Apple Photos Master Data |
| apmx64 | Rohitab API Monitor x64 Capture Data |
| apmx86 | Rohitab API Monitor Capture Data |
| app | Alphacam Punch Post Data |
| ThecusOS Application |
| Wii U Game Data |
| appcache | HTML5 Application Cache |
| appcontent-ms | Microsoft Windows Application Content |
| appdata | VMware Workstation appData Data |
| appdownload | Apple App Store Partially Downloaded App |
| appicon | VMware Workstation appData Icon |
| appinfo | VMware Workstation appData Cache |
| appinstaller | MSIX AppInstaller Setup Data |
| appl | BoxGrinder Appliance Data |
| applace | Apple Photos Place Data |
| apple | Apple AppleSingle Data |
| application | ClickOnce Deployment Manifest |
| apr | Arcplan Enterprise Repository |
| Gerber Aperture Data |
| MicroSim PCBoard Aperture Information Report |
| SAM Alignment Probabilities Data |
| apr_lib | Altium Designer Aperture Library Data |
| apsmartalbum | Apple Aperture Smart Album Data |
| apt | Alphacam Punch Tool Data |
| Gerber Aperture Data |
| Maven Doxia Almost Plain Text Data |
| Nimbus 7 SAMS APRIORI Data |
| apv | Acerose Password Vault Data |
| ApiViewer API Database |
| EdiAPV Data |
| apvault | Apple Aperture Vault Data |
| apversion | Apple Photos Version Data |
| apvolume | Apple Photos Volume Data |
| apvr | BenMAP APV Configuration Results |
| apw | AnyPassword Data File |
| Aspen Plus Document |
| apx | Lotus Approach Paradox Specific Information |
| apy | Arcplan Enterprise Layout |
| aq | Ancestral Quest Database |
| aq1 | AptiQuiz Test |
| aqa | Ancestral Quest Database Index |
| AptiQuiz Test Result |
