After seven seasons, the weird little corner of the CW’s Arrowverse known as DC’s Legends of Tomorrow was cancelled in April.  Originally meant as a starring vehicle for Arthur Darvill, the show quickly outgrew its original premise and embraced its weirdness.  With approximately 22 main characters coming and going over the seven years, the show was always able to move characters in and out as the story required, or as the wants of the cast required.  I honestly doubt we ever see a show quite like this survive for as long again.