I'm guessing you've seen the Infineon (formally Cypress) PSoC [0] stuff too? Both analogue and digital peripherals that can be configured mostly arbitrarily.
There are also some neat mixed-signal parts from Dialog [1] - no MCU but interesting analogue and digital blocks all the same.
The analog configurability of PSoCs is perhaps a little less flexible than you might be led to believe. There's a small number of analog components which can be linked to pins or to each other through a limited number of non-uniform interconnects. It's certainly useful, don't get me wrong, but I'd hesitate to call it arbitrarily configurable.
There are also some neat mixed-signal parts from Dialog [1] - no MCU but interesting analogue and digital blocks all the same.
[0] - https://www.infineon.com/cms/en/product/microcontroller/32-b...
[1] - https://www.dialog-semiconductor.com/products/greenpak