Personally i don't think it's a good solutions to save all seed words in one location unless it's encrypted with more words as suggested above. There is no metal protected from burn or other kinds of damage.
Passphrase was posted above by some users but it is not an encryption. It is called seed phrase extension with an extra word. But you can decide to encrypt your passphrase with an open source tool or you can encrypt it on computer if you have it on a USB flash or memory card but detached from the device and stored in somewhere safe.