FilamentSwatches is an app that allows you to manage and store your different 3D Printing filament colors.
In addition, you can use the app to read from and write the swatches to NDEF-compliant NFC tags that you can then stick onto your physical printed filament samples.
This allows you to form a digital link between your physical samples and information about the filament that was used to print them.

The app encodes the filament information as a URL that is saved onto the NFC tag. This way, any NFC reader can be used to view the information saved on the tag.

Personally, I use the app together with 25mm NTAG215 black NFC tags that I stick on 3D printed mini filament spools.