Planetary nebula
We know of about 3,000 of these nebulae in our galaxy, compared to 200 billion stars.<ref>Parker Q.A. et al. 2006. The Macquarie/AAO/Strasbourg H-alpha Planetary Nebulae Catalogue: MASH, MNRAS 373, 79</ref> Their very short lifetime compared to a star is why there are not that many compared to stars. They are found mostly in the plane of the Milky Way, and there are more and more the closer you get to the center of the Milky Way.