The website
https://codenames.info/ has a list of WWII operation code names. I found it via a web search and thought first it was some copy of wikipedia, but it actually has a lot of details about little-known operations, at least for the Artic area which I checked. From my (limited) experience, it seems heavily focused on naval and aeronaval matters in this area at least, missing AFAIK all land battles in this theater before fall 1944.
Edited: actually, I found land battles linked to the Finland area, not Artic