I can absolutely vouch for HelloChinese, I’ve enjoyed it a lot more than Duolingo but definitely try both! Great list, recommend everything on here but here’s a couple extra things I use:

Apps

• Pleco – Dictionary app
• 微信读书 – Audio book app

Youtubers

• Grace Mandarin Chinese
• Katherine’s Journey to the East

Websites

• Bilibili – Chinese Youtube
• Baidu – Chinese search engine
• LINE – Online dictionary
• Chinese Grammar Wiki – Self explanatory

Anki

• Ultimate Chinese Deck – Deck of Chinese words in order of common usage. Definitely look up example sentences and watch content after learning new words so they stick
• MorphMan – Add-on that generates sentences for you to learn and read from