Ducky makes keycaps for backlighting in "Nordic" layout for their regular keyboards. "Nordic layout" is Swedish/Finnish, Norwegian and Danish combined. Unfortunately, they place Swedish/Finnish at the top so that only those (ÅÄÖ) are backlit instead of the correct symbols for Norwegian (ÅÆØ).
But you would still have to use blanks for the keys that are in special sizes for ErgoDox.
Sometimes, there is a group buy for a key set on PimpMyKeyboard.com or here which contains an ErgoDox kit as an add-on. However, custom key sets for any European layout in general is unusual and it is very unusual for there being an ErgoDox and a kit for any European layouts in the same group buy.
I use Swedish layout. My keycaps are for the wrong language (UK or DE) and/or vintage, "blank" without legends altogether or with custom printing from
WASD Keyboards. Getting
nice new keycaps in Swedish (only) seems nearly impossible.
I do have an ErgoDox (that I do not use very much), and on that I have custom-printed keycaps from WASD Keyboards - where the keys are the same as in a regular row-staggered keyboard layout.
Where the keys are special for the ErgoDox, I do instead use blank keys from WASD Keyboards in different colours for showing their functions.
If I was going to add labels to blank keys, I would start with some light-coloured keys. Then print on water-transfer decal paper and attach those decals to the
front of the keycaps where they wouldn't suffer my fingers hammering on them.