Captivating Poke Puff says to put any number of Basic Pokemon you find in your opponent's hand onto their Bench. Does this allow you to put more than 5 Pokemon on the bench?
No, Captivating Poke Puff does not allow you to exceed the normal limits of the game. You can put any number of Basic Pokemon onto your opponent's Bench up to the maximum size of the Bench.
Source: Steam Siege FAQ (2016-08-04), TPCi Rules Team (2016-08-04)

Relevant cards

Note: All applicable cards may not be listed below.
XY11_99