# Library

[Filler](/configure/library/filler) lists are collections of videos that you may want to play during [Flex](/configure/channels/flex) time segments. Flex is time within a channel that does not have a program scheduled (usually used for padding).

[Custom Shows](/configure/library/custom-shows) are sequences of videos that represent a episodes of a virtual TV show. When you add these shows to a channel, the schedule tools will treat the videos as if they belonged to a single TV show.