Just remembered a funny one: Auger/Augur. I had a good laugh reading that quote I received, that was saying the holes would be made by an augur. Maybe to learn if the foundation would hold for long?
Also, I really hate reading 'dialouge' or 'prolouge', so surprisingly common! Athrough I don't know if it's by English speakers or not. I know I make a lot of stupid English mistakes myself.
One from an English speaker, for sure (I know them): udder instead of utter. " An udder lack of..."