While wondering around Aliexpress offers I stumbled upon a black box coded "HLK-PM01" that is said to be a 90-260Vac to 5Vdc at 600 mA output.
There is also an interesting 3.3V @1 A as HLK-PM03 and 12V @600 mA as HLK-PM12. The producer has even a website www.hlktech.net.
These blocks are the best solution so far I have encountered for DIY projects that need to run off an AC outlet, let alone the bulky "USB" chargers. And HLK-PM03 provides 3.3V that are needed for ESP8266-based projects.
I've ordered a couple of 3.3V modules, also because an positive review you can find on a .dk website (for HLK-PM01).