I've also had a lot of fun with those cheap MCUs, for 20 cents, it's kind of insane value: 32-bit core with dma, enough flash and memory to do most of basic stuff, decent peripheral (ADC, timer, i2c, spi, uart). Recently i made an audio spectrum on the cheap ssd1306 screen).
And the surprising thing is its IDE is based on Visual Studio Code, not Eclipse like other vendors (Yeah you, i talking to you, ST), so it's much sleeker.
The CH32V003 has been around for a few years, and there are also now a 002, 004, 006 with more RAM and Flash (up to 8k + 62k), a better 12 bit (vs 10) ADC, and an updated CPU core with multiply (but not divide) erasing the last advantage of Cortex-M0. Also an expanded 2-5V power supply range (up from 3.3-5V) plus of course a bit of margin on both ends.
And pretty much the same low low price, though the 006 for example doesn't come in an 8 pin package option.
There is now also at the same price the CH570D at also the same price, with 16k RAM, 256k flash, USB, and a 2.4 GHz packet radio similar to things like the nRF24L01. I don't think it's available in bulk yet, but a dev board with a couple of extra chips has been available since early this year:
And the surprising thing is its IDE is based on Visual Studio Code, not Eclipse like other vendors (Yeah you, i talking to you, ST), so it's much sleeker.