This is a list of common misspellings. Anyone is free to add things to this list.

accomodation

Should be accommodation

cemetary

Should be cemetery

Comores

Comores is the French spelling. The English spelling contains an "o" instead of an "e".

desert/dessert

a desert is a type of biome, while dessert is what you eat after a meal.

humourous

humourous is rather an archaic spelling of humorous, which is the standard spelling in all varieties of English.