Dictionaries
Jisho
A free online dictionary that allows searches in romaji, hiragana, or kanji. You can also draw the kanji to identify it.
Midori
Midori is very similar to Jisho, except that it is on iOS.
Zokugo Dictionary
Zokugo is an online free dictionary specifically for casual slang or similar words. It is only available in Japanese.
Vocabulary
JPDB.io
JPDB.io is a notecard review program similar to Quizlet or Anki, but it has several pre-made decks to allow you to learn vocabulary and kanji used in popular anime, shows, manga, and more. It uses spaced repetition and you can also add your own decks.
Anki
Anki is highly customizable and allows for users to modify almost any aspect of their notecards. It also uses a spaced repetition system (which you can also modify). However, some students may find Anki too complex and in-depth to use on a regular basis. Creating a deck is often difficult at first, especially when trying to enter furigana. Another con is that, for the free version, it is not very portable compared to Quizlet.
Quizlet
Quizlet is an online flashcard resource that can be used either on the website or app. Premade decks can be searched for, or you can make your own. The interface is very simple and easy to understand. A known issue with Quizlet is that much of the platform is paid and there are a lot of ads, which can make the experience much less enjoyable than Anki unless Quizlet Plus is used.
Grammar
Takoboto
Takoboto is a Japanese dictionary website, but they also provide grammar references. The grammar search portion of Takoboto allows users to look for specific grammar points.
Tae Kim Japanese Guide to Grammar
Tae Kim’s Guide to Japanese Grammar is an excellent resource to use when confused about different pieces of grammar that may not make sense or are highly nuanced. This resource is recommended for beginner to lower intermediate learners of the language or the following levels: JPN 1011 to JPN 3022/JPN 3031.