Dreamt and its derivatives are the only English words that end in mt

'Dreamt' and its derivatives (undreamt, daydreamt, redreamt, etc.) are indeed the only common English words ending with 'mt'. This is a unique orthographic pattern in English. While some very obscure or coined words might end in 'mt', 'dreamt' and its forms are the only standard, widely recognized English words with this ending. The past tense 'dreamt' (alternate to 'dreamed') is a standard irregular verb form.