Here is the start of many examples from the history of English, but they won’t go into that category, I just think they are neat words perhaps not well know to some speakers.
Seethe and sodden are the same word, seethe being the present tense form and sodden the past participle. The change from th to dd is explained by Verner’s Law where the accent falling on a different syllable in each form resulted in sound changes like th to dd.
Seethe means to soak something in liquid, sodden refers to the perfective: completed action’s result.
(see Roger Lass, Old English, A Historical Linguistic Companion)