NomNom is the most complete savegame editor for No Man's Sky, and also shows contextual information around the data you are about to change. You can also easily look up each item individually to examine its attributes, independently of a save, or get other useful information that are not related to a specific save (but enhanced if one is loaded).
The features of NomNom can be divided into the different main parts you will see below. A detailed list can be found in the FEATURES file.