Janis Joplin and Jimi Hendrix could be featured on upcoming postage stamps. The Washington Post has obtained a recent list of approved subjects for stamps over the next few years, and the '60s music icons are in the 2014 "Collectible" list with their stamp designs in development.

Meanwhile, collectible Elvis Presley and James Brown stamps are reportedly in development for 2015. A number of other music stars, including John Lennon, Jim Morrison, and Michael Jackson, are on the "year to be determined."