In an effort to minimize forum spamming and / or constant "promotional noise" we (mostly) steer clear of tool recommendation threads. Take a peak at the Charter for the particulars.
I suggest that you search phrases such as "typo generator", "misspelling generator", or "common misspellings". The search results for those phrases should get you started.
[edited by: Webwork at 8:59 pm (utc) on Oct. 18, 2007]