Off the top of my head, a Craft Monster can never have too many:
Letter Sets (PC Fonts are just not the same)
Vintage Trugs (endless uses for all stashing possibilities)
Baskets... all sizes
Glass Jars and Pots (glass or plastic as long as they are transparent!)
Journals and sketchbooks
Craft Books (ahem.)
Buttons (also, ahem.)
Baskets for all old scraps
Stickers and Labels
Cups of Tea! (ok, AND cake)
Coloured Pens - just because
Tape Measures (all over the house and in various handbags)
ADD TO MY LIST!!!
What else are we Crafters seriously in need of hoarding....?