Endeavour

Endeavour is the sword that Hiccup Horendous Haddock III uses in the books but is not seen in the film adaption

Use in the books
Hiccup uses Endeavour in all the books from fighting Alvin the Treacherous or Norbert the Nutjob and even the Hairy Scary Librarian and he always keeps it with him incase he is attacked by Driller-Dragons, The Monstrous Nightmare even a dumb Gronkle, that sword may be alot like Hiccup for most swords of the other Vikings like Stormblade or Heart-Slicer are big and scary but Hiccup's sword is small so it is much like him, execpt more deadly. For some reason Endeavour was not in the film and Hiccup used an axe Stoick the Vast gave him.