Black Foam Board by Elmer's
Like its white counterpart, these black foam boards pack a lot of value for a very affordable price tag. I keep a few of these by my side and use them for almost every shoot in my home studio.
While the white boards are great for bouncing light, black boards are great for reducing light. And if you caught my tutorial on avoiding reflections, you'll understand how valuable the matte surfaces can be. Plus, they can also double as blacked-out backdrops for your product shoots. Elmer's makes great quality boards, but there are even cheaper options out there. You can find these at any local craft store.