This will likely be resolved by someone simply tossing a removal spell at Hushbringer since it dies to a gentle breeze, but should it stick around a while and shut down a player at your table, they may opt for player removal instead
Imprisoned in the Moon, Leyline of Anticipation, Shark Typhoon, and Teferi's Ageless Insight are all more than playable and would work well
A cheap, aggressive threat that turns Relic of Progenitus and similarly efficient graveyard hate into burn engines sounds intriguing to build around and potentially quite powerful
These effects are designed to end games quickly
I guess the Clamfolk solve all their problems by basically paying them off
Enter the budget tutors, affordable search effects that find the cards you need, though not without restrictions