The constellation Triangulum lies close to overhead in northern skies on December evenings. It contains the Triangulum galaxy, a gorgeous pinwheeling spiral.
Auriga the Charioteer is a north circumpolar constellation best viewed on autumn and winter evenings. Its star Capella is the sixth brightest star in the sky.
In Northern Hemisphere autumn (Southern Hemisphere spring), you can see some constellations representing a "celestial ocean in the sky" to early stargazers.
Microscopium the Microscope is a constellation with very dim stars. It holds a star, AU Microscopii, that has a disk of dust that is probably forming planets.
Equuleus the Little Horse is a diminutive constellation that lies south of the Summer Triangle. September nights are a great time to view the Little Horse.