The Perler sprites have small bases so they can stand upright.
Kirby's Adventure Perler Bead Nintendo Pixel Art - NES
Kirby's Adventure Perler Bead Set 3
Kirby Perler Beads
Kirby's Adventure - Israel
Kirby's Adventure
A Packet of Kirby's Needles London NE Plus No9 - New Zealand
Kirby in Robobot Armor Perler by jrfromdallas on DeviantArt
Baba O'Pearls
Kirby Perler Bead - Hong Kong
Kirbys Adventure Art - Sweden
Fuzz's Beads — Meta Knight, from Kirby's Adventure on the NES.
Kirby's Adventure NES Perler Bead Sprite by BigBossFF on DeviantArt