| yak | KayakFoundry 3D Design Documen |
| yang | YANG Designer Document |
| yaodl | SGI PowerFlip YAODL 3D Image |
| yar | StarBoard Document |
| yar | Yar Scene |
| ybk | Microsoft Encarta Yearbook |
| ydb | Yutori 7 Document |
| ydd | YANG Designer Document |
| ydl | SGI PowerFlip YAODL 3D Image |
| yes | Quick Bible Document |
| ygf | Y Graph Format |
| yka | Yenka Model |
| ymap | MindGenius v1 Document |
| z3d | ZModeler 3D Model |
| z3n | ZW3D Neutral Format File |
| zabw | AbiWord Gzip Compressed Document |
| zad | ZadGen Document |
| zax | Z-Axis 3D Office Design Document |
| zbr | ZBrush Document |
| zcl | Zoner Callisto Clipart Document |
| zcn | OmniPage Language Data |
| zdb | Avery DesignPro Design |
| zdg | ZiffNet ZView Compressed Document |
| zdl | Avery DesignPro Label |
| zds | Avery DesignPro Design |
| zdx | Avery DesignPro Clipart Index |
| zed | Compressed GEDCOM Document |
| zed | ZX-Edit Document Block |
| zgl | Compressed XGL Document |
| zgt | Oren-made Scientific Document |
