Fontdata uses typeface name information from various sources to validate if a given typeface name is (probably) already taken.
Just because a name isn't listed here, it does of course not mean nobody ever used it before for a typeface and it's free/o.k. to take.
The sources incl. typeface names from digital sources like MyFonts, Typekit, Google Fonts and foundry websites, but also non-digital sources like the so called »Seemann« (»Handbuch der Schriftarten« published 1926 incl. 6 supplements between 1927 and 1939), The Encyclopaedia of Type Faces (Jaspert, Berry & Johnson), Monotype Corp. faces and a list of many faces by American Type Founders.
Besides these main sources many font related Trademarks from the USPTO (United States Patent and Trademark Office) are included, too.
fontdata.com is maintained by Lars Schwarz.
You can search for typefaces with or without foundry prefixes (like »FF Meta« and »Meta« will work both, »FS Emeric« and »Emeric«, »ITC Benguiat®« and »Benguiat« and so on ...).
Even this tool is in an very early stage there is an API provided to programtically access the data.
These might come handy, too:
Type Foundries on Facebook, a single place collection of type foundry news posted on Facebook. Hourly updated.
Adobe Typekit Combos, inspiration for pairing Typekit fonts.