Scattered mostly along the Milky Way are stellar groupings called open clusters, randomly shaped families of mostly young, hot stars that are all gravitationally bound to each other. Most stars are born in such clusters, containing anything between perhaps twenty to a few thousand stars. All of the stars in a given cluster are about the same age, having formed together from the same nebula.
Here are two of my favorite open star clusters.
M46 is about 5400 light years distant and contains perhaps a hundred stars between the 9th and 13th magnitude. But of special interest is the tiny planetary nebula NGC 2438 seen as the tiny bluish ring among the stars of the cluster. M46 and NGC 2438 are believed to be not related, but instead in a chance alignment as seen from the earth.
M35 is another large cluster of about 200 stars. Most of the brightest stars are bluish white, although a few are yellow and orange giants. There is a curious absence of stars near the center of the group. But below and to the right in the image is a second, more distant cluster NGC 2158. NGC 2158 is believed to be about 16000 light-years away, while M35 is much closer, only about 2800 light-years.
(M35 was another of my favorite objects as a teenager, back in the 1950s.)