Tolliver, by CastIrony CastIrony (Joel Bernstein) · GitHub, generates a vector file containing a row of shapes in varying sizes. By importing this vector file into your CAM program, and cutting it out with a CNC machine, you can quickly identify the precise shape size needed to best achieve your desired fit.
Circles, triangles, squares, rectangles, and hexagons are supported. Squares, rectangles, and hexagons can have an optional dogbone effect added to the corners to compensate for the diameter of the mill: