The Medieval Scandinavian Motif Database was created from Inger M. Bobergs „Motif Index of Early Icelandic Literature“ and can currently be used to search a digitalized version of that index. You can thus search for certain words, as ‚creator‘, or a specific text, e.g. Gylfaginning and expect a useful result. If you can't find something, try using the full digitized Index found under Motif-Index, right next to the Home button. Many of the editions are no longer under copyright law and have been digitized and archived by Google or the Internet Archive. Wherever these digital sources were available, I have included the link. The editions from Altnordische Saga-Bibliothek are digitized but not available for anyone with an non-US IP-address.