Tolidef, Tulidef, Tullideff, Dilidaph, Dilidaph, Dillidaff, Dulledaphe, Twlydeff, Tillidaff, Tillidaiff, Tilliduff, Tuledefe, Tuledelph, Tulidaff, Tulidefe, Tullidaff, Tullidef, Tullidelph, Tullideph, Tuledeiff, Tulledaff, Tullidafe, Tulideffe, Tilledeph, Tulideff, Tulliedaff, Tulliedeph, Tullydaff, Tullyduff, Tulydef, Tylledaph, Tyllidaff - I think that makes 31, and I have only 202 people in my study, going back to 1317.
And yes it has helped me to break down a brick wall. My 5xgreat grandfather was born as Tullidelph and married as Tilledeph in Scotland, and when his son was born in Westminster, London he was called Tullideph. The son when he was next seen was married and having children in the City of London as Tillyduff. Forty years ago a researcher got my father's line back to Robert Tillyduff but no further. (My father's grandmother was Eliza Tilliduff.) It took a One-Name-Study to see all the different spellings that the name generated and enable me to morph Robert Tullideph etc. into Robert Tillyduff.