I know that Nixie tube clocks have become cliche but I just finished mines today.
I built it on a single pcb, well, except for the pin out for the mcu had to be changed... I swapped a cheapie esp8266 for a adafruit feather....
got a 12v to 170v switching boost regulator, a 12v to 5v module, ws2812b leds, and an esp8266 ntp time clock.