JWPce - JWPce is a free Japanese <--> English dictionary and word processor created by Glenn...
WaniKani - Learn around 1,700 kanji and 5,000 vocabulary words in about a one to two years.
zkanji - zkanji is a free and open-source study tool and dictionary of the Japanese language.
Kanji Koohii - Remember the kanji; mnemonics, smart dictionary, flashcards, spaced repetition.
WaKan - ?? (wakan) is a versatile tool for students of Japanese or Chinese.
Kanshudo - Master kanji, hiragana and katakana, along with Japanese grammar and vocabulary.