Planet
The smallest known planet is PSR B1257+12A, one of the first extrasolar planets discovered, which was found in 1992 in orbit around a pulsar. Its mass is roughly half that of the planet Mercury. The smallest known planet orbiting a main-sequence star other than the Sun is Kepler-37b, with a mass (and radius) slightly higher than that of the Moon.
Monte Iberia eleuth
The Monte Iberia eleuth (Eleutherodactylus iberia) is a small eleutherodactylid frog endemic to eastern Cuba. It is the smallest living frog in the Northern Hemisphere, about in snout–vent length. It is the third-smallest frog (and tetrapod) in the world, following "Paedophryne amauensis" and the Brazilian gold frog. It was first discovered in 1993 on Mount Iberia (Holguín Province), from which it gets its name, and exists in only two small regions of Cuba. Much remains unknown about this small creature.