Most known is very subjective, but the three best known for me are:
The Stingray Nebula (Hen 3-1357) is a planetary nebula. (The youngest known).
Sagittarius is a constellation which contains several well-known nebulae. These include the Lagoon Nebula (Messier 8), the Omega Nebula (Messier 17) which is also known as the Horseshoe Nebula or Swan Nebula, and the Trifid Nebula (Messier 20).
Eagle Nebula Orion Nebula
orion nebula
The Stingray Nebula, the youngest known planetary nebula.
The biggest known nebula is Tarantula nebula stand 160,000 light years from us. its wide is 650 light years (1 light years = 10 trillion km)
Andromeda, Milky Way These are galaxies ^ Orion Nebula Eagle Nebula
The orion Nebula
A nebula
The crab nebula is the debris formed in the supernova explosion.
The Eskimo Nebula is a planetary nebula (an area of gas surrounding, and orbiting around, a central star) that looks vaguely like a face with a furry parka hood. See the links for photos and more details.
The biggest known nebula is Tarantula nebula stands 160,000 light years from us. its wide is 650 light years (1 light years = 10 trillion km)