Mercury ⧃ Phases, given good seeing conditions.
The Moon ⧃ Lots of craters, mountains, and ridges - theoretical resolution limit of around 1.4 miles.
Mars ⧃ Around half a dozen dark albedo features, ice caps. Mars is easiest to view for the few months it is close to Earth around opposition, which occurs once every 26 months.
Mars’ outer moon Deimos can be seen if you use high magnification and block Mars and its glare from washing out the field of view.
Asteroids ⧃ Several thousand are easily visible. Ceres and Vesta are clearly not points of light like stars when they are close to Earth on a night of good seeing.
Jupiter ⧃ Around a dozen distinct cloud features, including the two red equatorial belts, brownish polar zones, white cloud belts, and the Great Red Spot. Jupiter’s weather is always changing, so it will rarely look the same over long periods of time.
Io is a yellow-orange disk that is clearly not uniform on nights of good seeing.
Europa is an off-white blank disk.
Ganymede is gray, with a slightly brownish northern hemisphere (Galileo Regio) visible on the best nights with a good high-power eyepiece.
Callisto is gray.
All of Jupiter’s 4 large moons regularly eclipse and transit the planet.
Saturn ⧃ The rings are easily visible at even very low magnification. On a good night you can pick out the Cassini Division and some muted cloud bands.
Rhea, Tethys, and Dione are relatively easy to spot close to the planet. Enceladus and Mimas are more challenging.
Titan is extremely obvious and noticeably non-stellar, perhaps slightly off-white in color.
Iapeteus can be seen easily when its brighter side is facing the Sun.
Uranus and Neptune ⧃ Non-stellar teal and blue disks respectively. On a good night you might be able to see Neptune’s moon Triton. Uranus’ 3 brightest moons are just beyond the reach of an 8” telescope most of the time.