Y - YSM
-
- Y - Compressed Amiga archive (YABBA)
- Y - Grammar file (Yaac)
- Y01 - Secondary index file (Paradox)
- Y02 - Secondary index file (Paradox)
- Y03 - Secondary index file (Paradox)
- Y04 - Secondary index file (Paradox)
- Y05 - Secondary index file (Paradox)
- Y06 - Secondary index file (Paradox)
- Y07 - Secondary index file (Paradox)
- Y08 - Secondary index file (Paradox)
- Y09 - Secondary index file (Paradox)
- Y64 - Commandos 2 Game Mission
- YADPCM - Raw Yamaha 4-bit ADPCM format
- YAL - Arts & Letters Clipart
- YAL - Data custom / nature.yal - Arts & Letters
- YAL - Arts & Letters Clipart Library
- YAM - Yahoo ! Auctions Data
- YAP - Castles & Catapults Game File ( Infogrames Entertainment SA)
- YAR - YAR Archive
- YAR - YAK archive
- YAR - Castles & Catapults Game File ( Infogrames Entertainment SA)
- YBAK - MindGenius Computer Aided Thinking File Backup ( Gael Ltd.)
- YBHTM - yBook HTML File ( Spacejock Software )
- YBK - Yearbook file (Microsoft Encarta)
- YBM - Bitmap image ( Face file )
- YBM - Face Bitmap
- YBTXT - yBook Text File ( Spacejock Software )
- YC - YACC archive
- YC - Archive - YACC (YAC.EXE)
- YC - YAC compressed archive
- YCBCR - Raw Y Cb and Cr sample file
- YCBCRA - Raw Y Cb Cr and alpha sample file
- YCM - Yu-Gi-Oh! Card Maker File
- YCM - Yugioh Card Maker file
- YCP - Image ASCII art
- YCT - YahELite Chat Transcript ( David J. Binette )
- YDC - Yu-Gi-Oh! Card Deck File
- YDC - Yu-Gi-Oh! Power of Chaos Card Deck ( Konami Group )
- YDK - Yusuf Data Recovery
- YDL - Yet Another Object Description Language
- YDL - Powerflip YAODL 3D Image File
- YDL - SGI YAODL 3d vector data Header
- YDR - Yu-Gi-Oh! Power of Chaos Replay File
- YEL - Yellow color separation
- YEL - Yellow Color Separation ( Adobe Systems Incorporated )
- YENC - yEnc File
- YENC - yEnc Encoded File
- YFS - Yahoo ! Player skin file
- YG0 - Paradox Secondary Index
- YG0 - Paradox Secondary database Index
- YG1 - Paradox Secondary Index
- YG1 - Database Index : Paradox secondary index
- YG2 - Paradox Secondary Index
- YG2 - Corel Paradox database secondary index file
- YG3 - Paradox Secondary Index
- YG3 - Database Index : Paradox secondary index
- YG4 - Paradox Secondary Index
- YG4 - Paradox secondary database index
- YGD - Yougoodai Playlist ( mode2 )
- YGF - yEd Graph Editor Y Graph Format ( yWorks )
- YGN - yGen Project File ( Spacejock Software )
- YGO - Paradox Database - related File
- YHF - Your Honey Frame Shape File ( HotBounce programming & development )
- YINS - Castles & Catapults Game File ( Infogrames Entertainment SA)
- YKEY - Castles & Catapults Game File ( Infogrames Entertainment SA)
- YLD - SMS Yield Monitor Data File (Ag Leader Technology Inc.)
- YLT - TheWord & Bible Companion Young 's Literal Translation Bible
- YM - Atari ST YM2149 Module / Song ( Atari )
- YM - Atari ST Audio
- YMA - YMAG Center Data Exchange File ( Ymag )
- YMAP - Ygnius Computer Aided Thinking File
- YMAP - MindGenius Computer Aided Thinking File ( Gael Ltd.)
- YMG - Yahoo ! Messenger File
- YMG - Yahoo ! Instant Messenger ( Yahoo !)
- YML - Javascript YML Document ( YAML )
- YML - YAML Document
- YML - Sailfish Yacht Analyzer XML- based Data File ( Techsail )
- YMP - MicroSim PCBoard Mapping File
- YMP - Yast Meta Package - YAST2 ( SUSE Linux Package Manager )
- YMP - YaST Metapackage File
- YMY - Castles & Catapults Game File ( Infogrames Entertainment SA)
- YN - Tuningwrench Audio Utility compressed file
- YN - Audio Utility Tuningwrench compressed file
- YNC - yEnc Encoded Files
- YNC - yEnc Encoded File
- YNN - Secondary index - Borland Paradox
- YNX - Midiprg Seqmax Seqprest compressed file
- YNX - Seqmax Seqprest Compressed Audio File
- YPCL - Castles & Catapults Game File ( Infogrames Entertainment SA)
- YPF - YahELite Configuration ( David J. Binette )
- YPK - MicroSim PCBoard Mapping File
- YPL - Yahoo ! Player Playlist
- YPS - Yahoo ! Instant Messenger ( Yahoo !)
- YPS - Yahoo ! Messenger Data File
- YPT - Cryptic File
- YRD - Yard Tracks File - FYM
- YRM - Command & Conquer Yuri 's Revenge Unofficial Multiplayer Map
- YRO - Command & Conquer Yuri 's Revenge Official Multiplayer Map
- YSE - Yamaha Studio Editor Session File ( Yamaha Corporation )
- YSM - Yamaha Studio Manager Session File ( Yamaha Corporation )
