If I use Dracovish V's "Slosh 'n' Crash" attack against Honchkrow V with its "Boss Pockets" Ability, do I get to do 120 more damage for each Pokemon Tool attached to Honchkrow V?
No, Slosh 'n' Crash only does 120 more damage regardless of whether one or more tools are attached.
Source: Brilliant Stars FAQ; TPCi Rules Team (2022-02-24)

Relevant cards

Note: All applicable cards may not be listed below.
SWSH9_114
SWSH9_114
SWSH9_88
SWSH9_88