Firestorm

Debuting in Action Comics #666 in 1991, this DC character emerged at the dawn of the Copper/Modern Age and has woven through the publisher's continuity for an impressive 26 years. With appearances spanning titles like Infinite Crisis and the Firestorm series itself, this is a figure who has kept genuinely rarefied company — sharing pages with the likes of Green Lantern, The Flash, Martin Stein, and Jason Rusch. The catalog count is modest, but at least one of those appearances carries real collector significance, making this a character worth tracking down for fans who love digging into DC's deeper corners.