Fritz X and Hs 293 I would think. Stand off range was limited, but sufficient to avoid shipboard AA fire which was all that really mattered. The USAAF had some earlier weapons that sort of worked but none of them proved reliable enough for regular use prior to the entry into combat of the German weapons.
Though depending on what you count as far as reliability goes, the Germans had remote controlled explosive motor boats in WW1 that did manage to score a hit and seem to have justified themselves as useful if limited weapons. I believe wire guided torpedoes were tested with some success prior even to the outbreak of WW1.