First, I created full-board gutters that would funnel the balls to the bottom of the board for the regular and fancy boards that Zack Freedman made, then I decided to create my own extended board that was covered on all sides with gutters. On this board, the ball collection is at the bottom between the endzones for convenience.
These are all of the custom tiles that I've made for Hextraction, although there are hundreds more made by Zach Freedman and the rest of the community. Each of the tile images has a link to it's respective thangs page where you can get a more detailed description and the STL file to print it.