To generate a list of all fonts available available with XeTex and XeLaTeX, use this command at your Unix command line:
fc-list : family
I found that command at this tex.stackexchange.com URL.
That command may also work with Windows, but I don’t have a Windows system to test with. Note that it took a little while to run the first time, then it returns almost instantly after that.
A list of XeTex fonts on a Mac OS X system
If it helps to see the output, when I run this command on my Mac OS X 10.10 system, I get this list of 170+ fonts that are available with XeTex and XeLaTeX:
American Typewriter Andale Mono Apple Braille Apple Chancery Apple SD Gothic Neo,Apple SD 산돌고딕 Neo Apple Symbols AppleGothic AppleMyungjo Arial Arial Black Arial Hebrew Arial Hebrew Scholar Arial Narrow Arial Rounded MT Bold Arial Unicode MS Athelas Avenir Avenir Next Avenir Next Condensed Avenir Next Condensed,Avenir Next Condensed Demi Bold Avenir Next Condensed,Avenir Next Condensed Heavy Avenir Next Condensed,Avenir Next Condensed Medium Avenir Next Condensed,Avenir Next Condensed Ultra Light Avenir Next,Avenir Next Demi Bold Avenir Next,Avenir Next Heavy Avenir Next,Avenir Next Medium Avenir Next,Avenir Next Ultra Light Avenir,Avenir Black Avenir,Avenir Black Oblique Avenir,Avenir Book Avenir,Avenir Heavy Avenir,Avenir Light Avenir,Avenir Medium Ayuthaya Bangla MN Bangla Sangam MN Baskerville Big Caslon Bodoni 72 Bodoni 72 Oldstyle Bodoni 72 Smallcaps Bodoni Ornaments Bradley Hand Brush Script MT Chalkboard Chalkboard SE Chalkduster Charter Charter,Charter Black Cochin Comic Sans MS Copperplate Corsiva Hebrew Courier Courier New Didot DIN Alternate DIN Condensed Euphemia UCAS Futura GB18030 Bitmap Geneva Georgia Gill Sans Gujarati MT Gujarati Sangam MN GungSeo Gurmukhi MN Gurmukhi MT Gurmukhi Sangam MN HeadLineA Helvetica Helvetica Neue Herculanum Hoefler Text Impact InaiMathi Iowan Old Style Iowan Old Style,Iowan Old Style Black Kailasa Kannada MN Kannada Sangam MN Kefa Khmer MN Khmer Sangam MN Kokonor Krungthep Lao MN Lao Sangam MN LastResort LiHei Pro LiSong Pro Lucida Grande Luminari Malayalam MN Malayalam Sangam MN Marion Marker Felt Menlo Microsoft Sans Serif Monaco Mshtakan Myanmar MN Myanmar Sangam MN New Peninim MT Noteworthy Optima Oriya MN Oriya Sangam MN Osaka Palatino Papyrus PCMyungjo Phosphate PilGi Plantagenet Cherokee PT Mono PT Sans PT Sans Caption PT Sans Narrow PT Serif PT Serif Caption Raanana Sathu Savoye LET Seravek Seravek,Seravek ExtraLight Seravek,Seravek Light Seravek,Seravek Medium SignPainter,SignPainter\-HouseScript Silom Sinhala MN Sinhala Sangam MN Skia Snell Roundhand STFangsong STHeiti STIXGeneral STIXIntegralsD STIXIntegralsSm STIXIntegralsUp STIXIntegralsUpD STIXIntegralsUpSm STIXNonUnicode STIXSizeFiveSym STIXSizeFourSym STIXSizeOneSym STIXSizeThreeSym STIXSizeTwoSym STIXVariants STKaiti STSong Sukhumvit Set Superclarendon Symbol Tahoma Tamil MN Tamil Sangam MN Telugu MN Telugu Sangam MN Thonburi Times Times New Roman Trattatello Trebuchet MS Verdana Webdings Wingdings Wingdings 2 Wingdings 3 Zapf Dingbats Zapfino
Some of those fonts aren’t too terribly useful for my needs, but in summary, if you want to see a list of fonts that are available with XeTex and XeLaTeX, I can confirm that this command works on Mac OS X systems. I installed my LaTeX environment with MacTeX.