I have a completed project up on my Tindie page in my profile, it's an ESP32 based input/output control board powered by PoE that was designed for ESPHome software.
Lately I've been working on a fully featured modern MP3 player with tiny OLED screen and a PCB the size of a credit card. I've been frustrated with every project on the web that has anything to do with playing MP3s, they all kinda suck and most don't go beyond the "hello world" equivalent of playing an MP3 file. So I'm making sort of a "core" base firmware that will include all the basics, like browsing for a file to play, creating/editing playlists, non-blocking interrupt driven playback, internet streaming, and an alarm clock. Others would then be able to extend the functionally of this core system by just directly using its documented libraries and classes. It's all based around an ESP8266 and the VS1053 decoder chip.