Curiosity got the better of me, so I hooked a multimeter in between a battery and some effect pedals. Once I remembered to change the lead from the voltage/resistance socket, I got the following:
Pedal mA Off mA On Barber Compact Direct Drive Clone 3.8 12.9 BYOC OD-2 4.9 8.2 (both boost and TS engaged) Phase 45 clone 5.7 9.2
I tried to test the Xtomp mini (a digital pedal), but it wouldn't power on from the battery.
And then I got bored, so didn't test any others. Might update this thread later if I ever get around to it.
For most of those pedals, the increase in draw when the pedal is on looks suspiciously like the extra current draw of the indicator LED. There's not really anything else changing.