The HLK-PM03 AC/DC converter can supply 3.3V from either 110VAC or 220VAC. This makes it perfect for small projects that need a 3.3V supply from mains voltage (like ESP8266 or ESP32).
Note: this module is used with mains voltage. Make sure you understand what you are doing and always be careful while building projects that deal with mains voltage.
Project examples: