Bitmap Fonts - s76/libgdx GitHub Wiki
LibGdx makes use of bitmap files (pngs) to render fonts. Each glyph in the font has a corresponding TextureRegion.
Hiero - a utility for converting a system font to a bitmap
Glyph Designer - a commercial bitmap font tool with a wide variety of options for shadows, gradients, stroke, etc.
FreeTypeFontGenerator - generating bitmaps for fonts instead of supplying a pre-rendered bitmap made by utilities like Hiero
Distance field fonts - useful for scaling/rotating fonts without ugly artifacts
gdx-smart-font - unofficial libgdx addon for automatically generating and caching bitmap fonts based on screen size. (Uses FreeTypeFontGenerator)