The Cleveland Museum of Art has just made over 30,000 images from their collections available for reuse under a creative commons zero license. Here’s a few examples of Medieval arms in their Armor Court.
Crossbow of Elector Augustus I of Saxony, c. 1553-1573. Source: Cleveland Museum of Art, Creative Commons CC0 1.0
Left-Handed Dagger or “Main Gauche” c. 1650. Source: Cleveland Museum of Art, Creative Commons CC0 1.0