The unicode-range CSS descriptor sets the specific range of characters to be used from a font defined by @font-face and made available for use on the current page. If the page doesn't use any character in this range, the font is not downloaded; if it uses at least one, the whole font is downloaded.
The font-style CSS property lets you select italic or oblique faces within a font-family. Italic forms are generally cursive in nature, usually using less horizontal space than their unstyled counterparts, while oblique faces are usually just sloped versions of the regular face. Both italic and oblique faces are simulated by artificially sloping the glyphs of the regular face (see font-synthesis for control over this).
The font-variant-ligatures CSS property controls which ligatures and contextual forms are used in textual content of the elements it applies to. This leads to more harmonized forms in the resulting text.