Tokyo has many beautiful city lights.
I introduce some city lights which I recommend.
Rainbow Bridge in Odaiba
The towers supporting the bridge are illuminated into three colors, red, white and green.
You can cross the bridge by foot.

Place: Kaigan, Minato-ku, Tokyo
Access: Odaiba Kaihin Koen Station (Yurikamome line)
Sky deck of Roppongi Hills
This building has the highest open deck in Japan.
In this building, there are shops, and movie theater, you can enjoy it, too.
Roppongi Hills

Place: 1-10-6 Roppongi, Minato-ku, Tokyo
Access: Roppongi Station (Hibiya line of Tokyo Metro or Oedo line of Toei Subway)
Observation platform of Tokyo Tower
Tokyo Tower has two observation platforms, big one and special one.

Place: 4-2-8 Shibakoen, Minato- ku, Tokyo
Access: 5 walk minutes from Akabanebashi Station (Toei Oedo line)
7 walk minutes from Kamiyatyo Station (Tokyo Metro line)
Mt. Takao
MICHELIN featured Mt.Takao as 3 star!
view from Mt. Takao
Place: Takao- cho, Hachiojishi
Access: Takao Sanguchi Station (Keio Line)
Observation platform of Marunouchi Building
I especially recommend this 5th floor.
You can see lighted up Tokyo Station.
Marunouchi Bulding
Place: 2-4-1 Marunouchi, Chiyoda-ku
Access(from Shinjuku): Tokyo Station (JR Chuo Line)
The Metropolitan Government
You can enjoy the night view with good wine, cocktail.
The Metropolitan Government
Place: 2-8-1 Nishishinjuku, Shinjuku-ku
Price: free!
Access: 10 walk minutes from Shinjuku Station
Sunshine 60
You can see Yokohama from here.
In this observation platform, there is much space, so you can relax.
Place: 3-1-1 Higashiikebukuro, Toshima-ku
Access: 8 walk minutes from Ikebukuro Station
by takashi