Yes. The constellations we see, in fact all star visible from earth make up just a small part of one galaxy. A constellation may have a handful of stars while a Galaxy has billions if not hundreds of billions.
Because of their age, elliptical galaxies are believed to have older stars and less gas and dust in their insterstellar medium than other types of galaxies, and thus their nebulae are less common. However, nebulae are presumed to exist in almost all galaxies; and some recent observations hint that the central black holes of elliptical galaxies may tend to preserve interstellar gas by preventing it from cooling enough for star formation.
The space in between galaxies is far larger than the galaxies themselves.
Nebulae and Galaxies
Galaxies are larger than solar systems. Galaxies contain solar systems.
Well... I guess you could say that... Nebulae are just really gas clouds... usually they form stars (inside galaxies) but a large enough one could form a galaxy by creating enough gravitationally bound stars. It isn't likely to happen now though. It did happen frequently during the early universe where there was essentially nothing more than massive nebulae but now the average density of hydrogen gas means at most two or three stars at a time.
It is larger than the average galaxy, since the majority of galaxies are dwarf galaxies. However, there are still lots of galaxies that are larger than the Milky Way. For example, in our Local Group, the Andromeda Galaxy seems to be somewhat larger than our Milky Way.
Nebulae are found in most galaxies
No, we believe that nebulae probably exist in every galaxy, and possibly between galaxies as well.
There are galaxies and nebula in every direction, including Aquarius.
Stars, Planets, nebulae, galaxies.
Many do, certainly. However, the very oldest galaxies have used up most of their starforming material by now. Spiral galaxies such as our own have lots and lots of nebulae. Often galactic rotation can start off bouts of star formation from the nebulae (both bright and dark) as they come under the gravitational influence of new stars in their neighbourhood.
Stars, star clusters, distant galaxies, galaxy clusters, nebulae, ...