When using Drampa GX's "Berserk" attack, must ALL Benched Pokemon have at least 1 damage counter or do you only need 1 Benched Pokemon with a damage counter on it to add the +70 damage?
If any of your Benched Pokemon have damage counters it will add the +70 damage. If it required all of them it would have said "all" or "each" in the attack text.
Source: TPCi Rules Team (2017-07-06)

Relevant cards

Note: All applicable cards may not be listed below.
SM2_115
SM2_142
SM2_160
SMA_SV80
SMA_SV80