The Norse Pantheon is one of the more detailed for which we have information, although like the Finnish pantheon a lot of what we know about it comes from a single person’s editorialized writing on the matter. Closely connected to the fairly well-documented Norse mythos, however, is the continental Germanic and Anglo-Saxon mythoi. Neither are well documented, and the one attempt to bring the Anglo-Saxon pantheon (in Dragon #263) created much of it from whole cloth. Of course, that’s pretty necessary with such sparse information.
There are many other characters in the various Norse sagas who could potentially be deities, and many of them are giants. Many of them, like the wives of the male deities, should be near-divine immortal beings; others such as Skadi and Aegir are full deities but whether they should be included in the giantish pantheon or not is something I will need to consider. Treating them in much the way Nathair Sciathach is handled may be best. In addition, for the purposes of the D&D multiverse, a tie-in to the Greek Gigantomachy might also be worthwhile. In addition, the Vanir is very lightly detailed in Norse mythology; some scholars hold it as a merging of pantheons from different groups, but considering the lack of comparative battle in what we know of Anglo-Saxon and Continental Germanic mythology while also having clear analogs of some of the Vanir deities, that seems unlikely. However, there’s enough of them to sketch out an ephemeral pantheon, while also describing the rest as highly reclusive and mysterious.