Falling into this category is Sigyn, and her sons with Loki Narvi & Vali. We know very little about these 3, save for what we discover in the story of Loki's binding. We learn how the two sons die. I think these two Gods also suffer, because Loki is their father. Loki is one of the dividing issues in American Heathenry (although I've been told this isn't the case among the Europeans). So his two sons fall into both the "we hardly know a thing about you" void and which side of the Aesir vs. Loki/Jotun issue they fall on.
For me, I love and honor Loki and Sigynn, so it was natural for me to have something created to represent their sons. Since there are no known representations of Narvi & Vali, I approached an artisan over on Etsy.com and commissioned this pair of altar stones from his shop Creative Art & Soul. The design is on front and back. It was easy to come up with the wolf as the symbol for Vali, as we know the Gods turned him into a wolf, and he devoured his brother Narvi, whose entrails were used to bind Loki to the rock. Just as obvious the wolf symbolism was for Vali, using entrails or a viscerated iconography, well, wasn't the route I wanted to go with. I had to come up with something I personally felt connected with Narvi. The following is the result.