Spacing Modifier Letters

Block from U+02B0 to U+02FF. This block was introduced in Unicode version 1.1 (1993). It contains 80 codepoints.

The Wikipedia provides the following information on block Spacing Modifier Letters:

Spacing Modifier letters is a Unicode block containing characters for the IPA, UPA, and other phonetic transcriptions. Included are the IPA tone marks, and modifiers for aspiration and palatalization.

Chart at Unicode.org (PDF)
Block at Decode Unicode