Kepler-10 System - An old sun-like star with a hot rocky Super-Earth (b) and a mega-Earth (c) in a Mercury like orbit. B is an airless Super-Earth covered in an ocean of magma with a high density, likely metallic. Its high density means its almost entirely composed of Silicate and metals. Had smallest measured diameter of any exoplanet (40% more than Earth, 4.5 Earth's mass, and nicknamed Vulcan by scientists) and is the first rocky exoplanet found by Kepler. Its daytime temperature is 1,500C, well over the melting point of Silicate and nearly that of Iron. The planet is glowing hot and lava pieces fly away from it like a cometary tail. Planet is similar to Corot-7b, but is around a more quiet star, making measurements more reliable, and thus this planet is the first certainly rocky planet discovered. Has circular orbit, so not likely a super-Io like that planet, instead considered a super-Mercury. Planet c was the first mega-Earth discovered and needed to be confirmed with the Spitzer telescope. Its diameter is 2.3 that of Earth and a mass of 17 that of Earth. It was thought rocky planets could get that big without absorbing enough gasses to make them gas giants. It is thought the planet never had an atmosphere because it is large enough to have kept it.
K2-3 System - Nearby red dwarf with a three transiting super Earths found by Kepler during its repurposed mission. The first two are scorching, but the third may be in the habitable zone. The closest transiting planets found that were luke-warm. The outermost is the nearest transiting potentially habitable planet. It is the smallest, yet most massive of the three (11.1 ME and 1.6 RE), classifying it as a Mega Earth.
BD+20594 System - Exceptionally bright star with a planet b, the largest terrestrial planet known and third known Mega Earth. It is about half the diameter of Neptune and over twice that of Earth, with 16 Earth masses.