Filler

In general, a filler is something that is used to fill gaps. Specialized meanings of the word "filler" include:

• Filler (animal food), dietary fiber and other ingredients added to pet foods to provide bulk
• Filler (linguistics), a sound spoken to fill up gaps in utterances
• Filler (materials), particles added to a matrix material, usually to improve its properties
• Filler (packaging), a machine designed to fill packaging, usually occurs in food packaging
• Filler (surname)
• Filler metal, metal added in the making of a joint through welding, brazing, or soldering
• Grain filler, a product that is used to achieve a smooth-textured wood finish
• Seat filler, a person who fills an empty seat during an event
• Star filler, a plastic insert in computer cables which separates wires

In media and entertainment:

• Filler (media), in television and other media, material that exists outside the story arc to pad out other material
• "Filler", song by hardcore punk band Minor Threat, from their debut E.P.

https://en.wikipedia.org/wiki/Filler