I was curious how common fires are on flights. Searching NTSB data for the keyword "fire" on part 121 flights (ie regular scheduled air carrier flights, this excludes general aviation, private jets etc)

  Year | # accidents
  -------------------
  2023 | 6
  2022 | 0
  2021 | 4
  2020 | 3
  2019 | 5
  2018 | 3

So rare but not super rare.

[1] https://www.ntsb.gov/Pages/ResultsV2.aspx?queryId=262a5b32-9...