This is in no particular order, just things I’ve found from places like Smashing Magazine or other list-type sites.  Most are open and you can use them for personal or commercial use– but check the licenses before you use them!

Gentium
“A typeface family designed to enable the diverse ethnic groups around the world who use the Latin and Greek scripts to produce readable, high-quality publications. It supports a wide range of Latin-based alphabets and includes glyphs that correspond to all the Latin ranges of Unicode.”

Cosmetica
The website’s language appears to be greek, but this is a great, clean, easy to read font that prints well.

District Thin
“The thinnest weight from GarageFonts’ District family, by Kienan and Dylan Smith. And it’s free! Give it a try.”

Delicious
“The Delicious is a font I designed because of my admiration for typography. It got a bit out of hand and in two years it resulted in a complete font family.”

Tallys
“Tallys is a font that is one degree slanted and has large caps, a small x-height and long ascenders. It comes (see also Fontin) with hybrid numbers and a complete character set.”

Fontin
“I’ve designed Fontin Sans to be a suitable sans companion of Fontin. With a nice classical appearance it will be a perfect match. Fontin will be rereleased in OpenType format (soon) as Fontin Semi (with a Bold Italic) to match new metrics an kerning. Be sure to check back once a while.”

Scriptina
A great script font.

Qlassik
Nice rounded font with some flare.  Bold is sweet too.

FF mt
“Erik Spiekermann’s most economical typeface ever. Employing obscure but powerful techniques like vwl mmssn and cap reduction, FF Mt uses up to 50% less paper, screen, and wall space than other text faces without a single condensed letter.”

FF Unit Rounded Bold
“In a semester project under Prof. Christine Wagner, students from the University of Applied Sciences Wiesbaden, Germany, designed a series of brochures about FontFont designers and their typefaces. Just have a look at the portraits of Xavier Dupré (FF Absara, FF Megano, FF Sanuk and more) and Martin Majoor (FF Scala, FF Seria).”