Green’s Dictionary of Slang

one who writes their tag or personal label on walls and other visible sites; a graffiti artist; also attrib.

1982		C. Castleman Getting Up: Subway Graffiti In N.Y. 21: ‘Taggers’ [...] have to write their names at least a thousand times before they can expect to be noticed by the other writers.
1998		Source Oct. 176: Middle class kids formed tagger crews [...] scrawling the numbers 1036 on the walls.
2000		W. Shaw Westsiders 367: He caught sight of a beautiful ‘burner’ down on the drab concrete walls [...] A ‘burner’ is the taggers’ name for one of those big, 15-foot-long works of art.
2013		J. Stahl Happy Mutant Baby Pills 139: Taggers had tagged the tree stump.