Halopedia is a wiki like this one, but its focus is the Halo Universe, while the Halo Costuming Wiki is focused on bringing fictional material out of the Halo universe and into our own in the form of costumes and props.
Here is a link to Halopedia (external link), we strongly suggest that you not add costume information to Halopedia because it is simply not appropriate there, but of course you're free contribute to it with information about the Halo universe, as Halopedia is massive, great place to find in-universe information.
Other Links of Resource Interest
If you are interested in Halo weapon props, be sure to check out our Weapons Hub. Each link takes you to things like Weapon Prop WIPs ("Work In Progress") links to articles on the 405th Forums which show forum members using many methods to create the weapon you've selected. These articles can provide insight into the creation of these weapons. Many Weapon Hub articles also have Weapon Prop WIPs Show Off links which are where 405th forum members are posting pictures of their finished (or nearly finished) props. Hub pages also include links to Reference Packs, Dimensional information, Pepakura Files, and even fan-made Blueprints where 405th forum members have come forward to share them.