Block from U+2100 to U+214F. This block was introduced in Unicode version 1.1 (1993). It contains 80 codepoints.
The Wikipedia provides the following information on block Letterlike Symbols:
Letterlike Symbols is a Unicode block containing 80 characters which are constructed mainly from the glyphs of one or more letters. In addition to this block, Unicode includes full styled mathematical alphabets, although Unicode does not explicitly categorise these characters as being "letterlike".