I've been using the 1" Filament Spool Shelf Honeycomb Brackets by Maoirae (Link Below) for a while and wanted a better way to identify open spools of filament. First made these without the tile holders but figured this was a better use of them, than sitting in the box in my drawer. I believe not all the tiles are printed the same thickness, because some are snug, but most slide in perfectly. If you find the tile to be too hard to slide in and out, sand the edge of the tile just enough to relieve the corners.

https://makerworld.com/en/models/88779#profileId-95016