I make my own, this is the primary board in my kitchen, it’s made from poplar wood. measures 16” x 24”. This one will go to my outdoor kitchen this spring, I already have the wood ready (hard maple) ready to make its replacement, 18” x 30”. I also use three smaller boards in the kitchen to avoid cross-contimainion.
On the subject of juice grooves, I made a board for someone where I included a groove on one side, but I’ve never found a need for grooves. To me they are just a place for crumbs and chopped foods to collect, making it more difficult to get them off the board. There are exceptions, but as long as I’m allowing meat to rest the appropriate time, I don’t have enough juice on the board to justify them. For those rare times when there is a lot of juice, I just keep wiping it with a chef’s towel.