Here are some tough ones: “Towing the line” is a real thing that people actually do. But most of the time when you see that written it’s a mistake, and the writer meant “toeing the line”.
“Soft pedal” and “soft sell” are both valid English phrases that are not identical but very close in meaning; so it’s easy to understand how some people get confused and write “soft peddle”, which is not a valid phrase.