In the generic case, I'd say STM32. It's a broad family, but the variants tend to be pin compatible. (most of them, but not the G series)
However, this is not a definite answer. There is no one size fits all. If you're looking for doing something like Bluetooth Low Energy, then I would recommend the nRF52 series. If you're looking for WiFi, I suggest the ESP32.
So, yeah, I'd say, standardise on STM32, but don't de afraid to derive from that if your use case has specific requirements.