We have metal chairs as overflow seating in our living room, but their legs would get stuck in the grout lines between tile making it hard to move them around (especially if someone is sitting in them and wanted to scoot). Grabbed the calipers to measure the chair legs (22.5mm), fired up tinkercad and made a quick/easy model that fits on the chair leg and slides between the tiles. 

I printed the files at 120% scale and wrapped the chair leg in electric tape creating a tight pressure fit. The electric tape is also rounded over the end of the chair legs to soften their impact to the slides.