Resources
Learning Chinese 中文學習
Most of these websites cover content suitable for Beginner and Intermediate levels.
Phonetic Alphabet Pronunciation Guide 國語日報ㄅㄆㄇ發音練習網: This page is helpful for learning and reviewing zhuyin/bopomofo as each symbol can be played by clicking the corresponding button. Keep in mind the correct order is reading from right to left, top to bottom.
Stroke Order Learning Program 標準國字筆順網 (English / Chinese): This program takes characters as input and walks through the proper sequence and direction of markings. It also supports Zhuyin.
Character History Videos (Chinese): This playlist traces the evolution of common characters to their original pictograms and ideas. Though there is no audio commentary and the notes are in Chinese, these can help anyone gain some insight into learning characters.
Huayu World 全球華文網路教育中心 (Chinese): This site is maintained by the Overseas Community Affairs Council, a government office of Taiwan. It contains a variety of learning resources and textbooks. Some pages can be translated to English.
Huayu World Supplementary Textbooks 台灣書院 (Chinese)
Children's Culture Center 文化部兒童文化館 (Chinese)
Living Mandarin 生活華語 (English / Chinese)
Quizlet Living Mandarin 生活華語 (English / Chinese)
Quizlet Kindergarten (English)
Chinese Learn Online: This podcast based in Taiwan is available on Google Podcasts, Apple Podcasts, and Spotify. The website also sells full lessons with transcripts and flashcards. Early levels are taught mostly in English and later levels are taught more in Chinese.
Easy Taiwanese Mandarin: This playlist contains interviews with native speakers including subtitles and translations as listening practice.
Apps
KTDict (iOS)
This app has a wide range of vocabulary, and also contains Taiwan-specific content such as alternate pronunciations and meanings. There are options to display Traditional rather than Simplified characters (in different fonts) and to change the voice to a Taiwan accent. (There is a paid version, but that is not required for search, offline use, or the other features mentioned above.)
Pleco (iOS / Android)
This app has a number of well-reputed dictionaries in its database along with Traditional/Simplified character and Cantonese support. In addition, it includes example sentences, cross-referencing, and some stroke order diagrams. (There is a paid version that provides extra features such as document reader and optical character recognition.)
Learn Taiwanese Zhuyin and Chinese (iOS / Android)
This app has flashcards displaying Zhuyin and Pinyin as well as Traditional characters, which can be played to level up and unlock other content. It is most suitable for those in the Beginner and Intermediate levels. The developer also has an app for Taiwanese Hokkien (a separate dialect), labeled as MinNan Taiwanese. (Note: This app contains many banner and fullscreen ads.)
Gus on the Go (iOS)
This paid app ($3.99) offers interactive lessons geared at children. Topics covered include colors, animals, food, and more. It is most suitable for those in Beginner Level 1. Characters are in Traditional and the recordings are by a native Taiwanese speaker. The developer also made an app for Taiwanese Hokkien, a separate dialect.