Kotu Requires making an account but only a username and a password is required. Try to improve your perception using the perception tests, as being able to perceive pitch accurately is by far the most important thing to learn in relation to pitch accent.
NALA-J Similar to kotu, without an account requirement and also a bit harder as it requires you to select where it drops.
Youglish An index of youtube subtitles,very useful to look up how a native speaker pronounces a given word.
Forvo A website where people can upload themselves pronouncing a word.
Filmot Very similar to Youglish, it allows you to look up words in youtube subtitles. Main benefit over Youglish is that it doesn't have a daily query limit, though the search results tend to be worse.
Immersion Kit A database of Anime sentences with audio.
u-biq Some basic information on pitch accent, has information on names,verb conjugations and adjective inflections.
Notes by Kez Notes on pitch accent, written by the creator of kotu.
OJAD An online accent dictionary. Be careful with this, it's computer generated so it can be inaccurate.
Darius Japanese stackexchange answers
Kanshudo guide to Pitch Accent An introduction to basic pitch accent and related vocabulary. Ignore the advice given on guessing the pitch of words based on the fequency of a given pattern(Rule 3: If in doubt, guess 平板).
日本語標準アクセントの概要 An English verision is available by clicking on the top right link. This is quite academic and has some of the worst notation I've ever seen.
WasedaX edx course A edx course on the pronounciation of japanese.
名字アクセント辞典 An online dictionary for Japanese last names. It can be innacurate, you should still be listening for it in native content and/or looking it up on Youglish,Forvo, etc.
Tofugu guide on Japanese prononunciation A guide on how to pronounce different japanese sounds and the positioning of your mouth to do so.
shuudo-u.ac.jp & part 2 Short read on some pitch accent phenomenon,these are part of a large series of lecures.
日本語のイントネーション website written by the author of 日本語のイントネーション
Strategies for Acquiring Pitch Accent in Japanese A video by a high level learner on how to go about acquiring pitch accent.
Yudai sensei A native japanese speaker who makes videos on pitch accent.
Pitch Accent for Absolute Beginners By Yudai Sensei.
Verb Pitch Accent and Verbs Conjugations
The Very Basics of Japanese Pitch Accent | 2 Rules and 4 Patterns
Introduction to Japanese Pitch Accent
Fluent Forever video on Pitch Accent
Intonation in Japanese "sentence-ending particles" 'よ' and 'ね' An example of how intonation is used to convey meaning in Japanese.
Dogen Makes japanese skits and also has a series on Japanese pronounciation, most of it is available at his Patreon
つたえるはつおん Channel introducing various aspects of Japanese pronounciation, targeted at learners.
UBC eNunciate useful channel on the sounds of Japanese.
日本語の発音: Pronunciation of Japanese
VIZ話し方教室 A youtube channel targeted at those wishing to be voice actors, announcers or in other similar fields.
NHK 日本語発音アクセント新辞典 The best resource on pronunciation. There is also a mobile application.
新明解 A dictionary for Japanese natives that contains some information on pitch accent, second to the NHK in utility.
The Sounds of Japanese An introduction to the phonetics and phonology of Japanese intented for those studying Japanese lingustics.
日本語アクセント入門 Covers various japanese accents.
解説：アクセントの平板化 An article on the recent trend of more japanese words becoming unaccented. Another similar article.
日本語アクセントが平板化 若者からひたひた進行中 An article on the tendency for young people to unaccent words.
これが今の日本語だ！ オヤジのためのアクセント入門 On the NHK accent dictionary 2016 update.
kansaiben.com Website for people self-studying Kansai-ben.
京言葉 Website centered around Kansai-ben.
わたさんの大阪弁アクセント講座 Very useful resource on Oosaka-Ben.
近畿日本語アクセント辞典 A online dictionary and notes.
関西弁３文字言葉イントネーション辞典 Electrophile list of the pitch accent of various words in Kansai-ben.
京阪アクセント辞典 An online dictionary for Kansai-ben. It is currently down.
YouTube関西弁講座-大阪おっちゃんねる- A channel on all things Kansai-ben.