Below is a list of light bulb types used in 2018- AUDI A1 lighting system, covering hatchback vehicles.
Headlight bulb: low beam - H7 / high beam - H15
Parking light bulb: H15
Front indicator/turn signal bulb: WY21W
Daytime running light bulb: H15
Rear indicator/turn signal bulb: PY21W
Tail light bulb: W16W or P21W
Brake light bulb: P21W
Back-up light bulb: P21W
Rear fog light bulb: P21W
Interior light bulb: W5W
Reading light bulb: W5W
Light bulb sizes for other AUDI A1 generations: A1 (8X)