More to explore:
make your own sanding blocks
sanding block tip
Make your own custom sanding blocks
Wooden Castle Blocks: These are very sweet.
Quick fix to when you are in need of a sanding block, and all you have is sanding paper.
Profile Sanding Block
Edge Banding With Iron-On Veneer Edging - Article | The Family Handyman
Anatomy of a block plane
Making a block plane into an edge-trim plane, Popular Science, circa September 1918
Not a total fan of boring hole on any kind of metal hand plane. An alternative that I think of is use rare earth magnet to affix the fence to the plane body.
Get a grip on corner blocks with a clamp block