Nix Owner's List
Records of who owns which nix are kept in the artist's description area of the adopt sheet on deviantart. Click the thumbnail of the sheet to go to its page. Records of individual customs which do not yet exist as a submission on dA are kept here.
Sugarnix
Single Images
Sheets
Click on any image to go to the sheet's sumbission page on deviantart. The list of owners for each individual nix on a given sheet can be found in the artists' description area of the submission.