I have assembled a list of the most controversial Wikipedia articles from the data on this page: https://en.wikipedia.org/wiki/Wikipedia:Database_reports/Talk_pages_by_size

There are 66 pages from the main article namespace listed there, and they are, in order of total size of all talk page archives, as follows:

  1. Donald Trump
  2. Intelligent design
  3. Climate change
  4. Barack Obama
  5. Race and intelligence
  6. Jesus
  7. United States
  8. Catholic Church
  9. Homeopathy
  10. Circumcision
  11. Chiropractic
  12. Monty Hall problem
  13. Muhammad
  14. Gaza War (2008-2009)
  15. Evolution
  16. Gamergate controversy
  17. Abortion
  18. Sarah Palin
  19. Prem Rawat
  20. Christ myth theory
  21. World War II
  22. India
  23. Jehovah's Witnesses
  24. Cold fusion
  25. Climatic Research Unit email controversy
  26. September 11 attacks
  27. Atheism
  28. Anarchism
  29. George W. Bush
  30. Falun Gong
  31. Armenian Genocide
  32. Neuro-linguistic programming
  33. Israel
  34. Cities and towns during the Syrian civil war
  35. Jerusalem
  36. Mass killings under communist regimes
  37. Transcendental Meditation
  38. British Isles
  39. Libertarianism
  40. Kosovo
  41. Christianity
  42. Thomas Jefferson
  43. International recognition of Kosovo
  44. United States and state terrorism
  45. United Kingdom
  46. Acupuncture
  47. Israel and the apartheid analogy
  48. Syrian civil war
  49. Adolf Hitler
  50. COVID-19 pandemic
  51. Russo-Georgian War
  52. Second Amendment to the United States Constitution
  53. Tea Party movement
  54. Murder of Meredith Kercher
  55. Genesis creation narrative
  56. Historicity of Jesus
  57. Electronic cigarette
  58. List of best-selling music artists
  59. Shakespeare authorship question
  60. List of sovereign states
  61. Taiwan
  62. Michael Jackson
  63. 0.999...
  64. European Union
  65. Chronic fatigue syndrome
  66. Russian interference in the 2016 United States elections