File Viewers and Converters

File viewers and converters aren't really scripting tools, but even as a scripter you'll often need them anyway.

The "Features" column tells you more about the program's functionality:

"V" (View) means its main function is to view files.
"P" (Print) means it can be used to print files.
"C" (Convert) means the main function is to convert files.
"X" (eXtract) means the program can add files to and extract from archives.

By looking in the column designated "Scriptable" you can see if the viewer can be used in scripts:

"CLI" (Command Line Interface) means it can be used with command line arguments, i.e. batch files and PowerShell, or with the Shell or Run commands in KiXtart, VBScript, etc.
"OLE" means it supports OLE/COM, and thus can be used in KiXtart, Object Rexx, Perl, PowerShell and VBScript.

File viewers organized by file types

Archives (arc, cab, mht, rar, zip, etc.)
Bitmap Images (bmp, crw, gif, jpg, tif, etc.)
Databases
Multimedia (music & video)
Corel/Microsoft/OpenOffice (dbf, doc, mdb, odt, ppt, rtf, sxw, wpd, xls, etc.)
Portable Documents (pdf, xps, oxps)
XML & XSLT
Related Stuff

Archives (arc, cab, mht, rar, zip, etc.)
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
7-Zip	Igor Pavlov	X	CLI		Free (donations welcome)
ExtractMHT	Jared Breland	X	CLI		Free
IZArc	Ivan Zahariev	X	CLI		Free (donations welcome)
Universal Extractor	Jared Breland	X	CLI		Free
WinRAR	WinRAR	X	CLI

Bitmap Images (bmp, gif, jpg, raw, tiff, etc.)
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
CopyExif	Ken Reneris	C ⁽¹⁾	CLI		Free
dpMagic	dpMagic Software	V
ExifTool	Phil Harvey	V ⁽¹⁾			Free (donations welcome)
FastPictureViewer WIC RAW Codec Pack	Axel Rietschin	V ⁽²⁾	OLE
FastStone Image Viewer	FastStone	V+P+C			Free for Home Users (donations welcome)
FastStone MaxView	FastStone	V+P+C
FastStone Photo Resizer	FastStone	V+C			Free for Home Users (donations welcome)
FxIF (Firefox EXIF viewer)	Christian Eyrich	V ⁽¹⁾			Free
IrfanView	Irfan Skiljan	V+P+C	CLI		Free (donation/registration enables more file formats)
Multi threaded DCRAW	Dave Coffin & HeliconSoft	C ⁽³⁾	CLI		Free
RAW Image Thumbnailer and Viewer	Microsoft	V+P			Free (Validation required)
SImage	Ken Reneris	C ⁽⁴⁾	CLI+OLE		Free
STDU Explorer	STDUtility.com	V ⁽⁵⁾			Free for non-commercial use
Virtual Image Printer driver (Win32 only)	Tariel Ibadov	C			Free

Databases
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
Access Database Viewer	Free Labs Software	V			Free
RazorSQL	Richardson Software	V+C
Snapshot Viewer for Microsoft Access	Microsoft	V			Free
xBaseView	Mutex LLC	V

Multimedia (music & video)
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
Adobe Flash Player	Macromedia (Adobe)	V			Free
Flash Movie Player	Eolsoft	V			Free
Free CD to MP3 Converter	Eusing Software	C			Free
Free M4a to MP3 Converter	Maniac Tools	V+C			Free
MediaInfo Lite (media file analyzer)	KL Software	V			Free
QuickTime	Apple	V	OLE		Free
Real Player	Real	V			Free
SWF & FLV Player	Eltima	V			Free
SWF & FLV Player Pro	Eltima	V
SWF & FLV Toolbox	Eltima	C
SWF Live Preview	Eltima	V			Free (registration required)
SWF Video Converter	Eltima	C
Swiff Player	GlobFX	V			Free
Winamp Media Player	Winamp	V			Free
Windows Media Player	Microsoft	V	OLE		Free

Corel/Microsoft/OpenOffice (dbf, doc, mdb, odt, ppt, rtf, sxw, wpd, xls, etc.)
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
Access Database Viewer	Free Labs Software	V			Free
Excel Viewer	Microsoft	V+P			Free
Powerpoint Viewer	Microsoft	V+P			Free
Save as PDF or XPS for MS-Office 2007	Microsoft	C			Free
Snapshot Viewer for Microsoft Access	Microsoft	V			Free
STDU Explorer	STDUtility.com	V ⁽⁵⁾			Free
TextMaker Viewer	SoftMaker	V+P			Free
Visio Viewer	Microsoft	V+P			Free
Word Viewer	Microsoft	V+P			Free
WordPerfect Lightning	Corel	V+P			Free
xBaseView	Mutex LLC	V

Portable Documents (pdf, xps, oxps)
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
Adobe Reader	Adobe	V+P	CLI		Free
doPDF (PDF printer)	Softland	C			Free
Doro (PDF printer)	the sz development	C			Free (donations welcome)
Drumlin PDF Reader/Publisher	Drumlin Security	V+P			Free
Foxit Reader	Foxit Software	V+P	CLI		Free
MUPDF	Dirk Paehl	V+C+P ⁽⁶⁾	CLI		Free
Office Convert PDF to Doc Text RTF	OfficeConvert.com	C
OXPS to XPS converter tool for Windows 7 SP1/Server 2008 R2 SP1	Microsoft	C			Free (validation required if not through Windows Update)
PDF2HTML	Mikhail Kruk	C	CLI		Free
PDF2Word Online	BCL Technologies	C			Free
PDF995 Suite (PDF printer+)	Software995.com	C			(free version displays ads)
PDF-XChange Viewer	Tracker Software	V+P			Free
PDFZilla	PDFZilla.com	C
Save as PDF or XPS for MS-Office 2007	Microsoft	C			Free
STDU Explorer	STDUtility.com	V ⁽⁵⁾			Free
Sumatra PDF	Krzysztof Kowalczyk	V+P+C ⁽⁷⁾	CLI		Free
Text Mining Tool	Text-Mining-Tool.com/	C	CLI		Free
XPS Viewer	Microsoft	V+P	CLI		Free
Zilla PDF to TXT Converter	PDFZilla.com	C			Free

XML & XSLT
Product	Programmer / Manufacturer	Features	Scriptable	Download	Purchase
AltovaXML	Altova	V+C	OLE		Free
XML Starlet	Dago et al	V	CLI		Free

Notes	1	With CopyExif, ExifTool and FxIF you can read and modify an image's EXIF data, but you cannot view nor change the image itself
	2	With FastPictureViewer WIC RAW Codec Pack you can view RAW images from Canon, Nikon, and others in Windows Explorer too
	3	DCRAW is a command line tool; it can convert RAW images and read metadata, but it cannot be used to view images
	4	SImage consists of SImageUtil.dll and SImg.exe; SImg.exe is a command line tool (wrapper for SImageUtil.dll), SImageUtil.dll is a DLL to be used for scripting; both can resize images and read metadata, but they cannot be used to view images
	5	STDU Explorer adds a preview pane to an otherwise very Windows Explorer like window with all of Explorer's context menus
	6	MUPDF contains a PDF viewer plus 6 other command line PDF utilities
	7	SumatraPDF can save PDF files as Unicode text (discarding all formating and graphics, of course)