Angel

The angel is a divine being, commonly in the form of a beautiful human with a glowing golden halo and white feathery wings. Depending on the rank and type, the angel may have several sets of wings, or take other shapes altogether. They are typically in the service of gods or other higher beings, acting out the plans of their masters, in manners that may be difficult for mortal races to fathom.

Source
The angel originates from the abrahamic religions. Rabbinic literature describes an angelic hierarchy. The Mishneh Torah, written by the rabbinic scholar Maimonides describes ten ranks of angels. Similar are the descriptions in Zohar, Maseket Atzilut, Berit Menuchah and Reshit Chochmah, although the ranks and angelic classes vary. More: Jewish Angelolgoy

Different angel-like creatures can also be found in Zoroastrianism, where a form of a "guardian angel" called Fravashi exists.

Angel classes

 * Chayot Ha Kodesh
 * Ophanim
 * Erelim
 * Hashmallim
 * Seraphim
 * Malakim
 * Elohim
 * Bene Elohim
 * Cherubim
 * Ishim
 * Elim
 * Shinanim
 * Tarshishim

Notes:
 * Ishim are said to be made from fire and snow and seem to be closer to the affairs of humans than the other angelic beings.
 * Cherubim once protected the Garden of Eden.

Media
Angels appear in the following media:

Movies and TV-Series

 * Supernatural - TV-Series, from 2005 - present, starring Jensen Ackles, Jared Padalecki, Misha Collins...
 * Misha Collins is playing the role of "Castiel" an Angel, who appears in the first show called "Lazarus Rising" of season 4. He is one of the many angels showing up throughout the show, alongside their opponents, the Demons.
 * Dogma - from 1999, starring Ben Affleck, Matt Damon, Alan Rickman, Salma Hayek...
 * Matt Damon is Loki and Ben Affleck plays the angel Bartleby, both are fallen angels.
 * Highway to Heaven, a TV-Series by Michael Landon, where he played the angel Jonathan Smith, who was sent back to earth to help people. Co-starring was Victor French as an ex-cop.
 * Lucifer - TV-Series, from 2016.

Games

 * Engel - a german RPG, published by Feder & Schwert/Uhrwerk Verlag Wikipedia article
 * Engel - a german RPG, published by Feder & Schwert/Uhrwerk Verlag Wikipedia article
 * Engel - a german RPG, published by Feder & Schwert/Uhrwerk Verlag Wikipedia article
 * Engel - a german RPG, published by Feder & Schwert/Uhrwerk Verlag Wikipedia article

Trivia

 * Lailah, or Laylah is an angel, who is the only one with a female name. This probably also is the roof of the Lilith myth.
 * Source:Lailah on Wikipedia
 * Castiel from the TV-Series Supernatural, means "Shield of God".
 * Source: Theophory in the Bible - Wikipedia article