Here are a few recommendations, though there’s plenty more out there:
Character learning/memorisation: Memrise/Anki Listening: CSLPod Reading: maayot or small books by Mandarin Companion Speaking: Tandem Writing: Skritter
We put together a schedule with a full list of tools if interested: https://www.maayot.com/blog/chinese-in-5-mins-a-day-learners-guide-schedule/