Here are a few costuming links that I found useful. You might find them handy, too.
Basic Clothing Guide: Headgear: Helpful illustrations.
Kit: Hats, hoods, caps & wimples: Descriptions, photos, and links.
Basic Clothing Guide: Female Clothing: Description of standard Viking/Dark Ages garb.
Female Headgear: Caps: I used this to make my caps, but increased the dimensions an extra 10 cm because I have a huge noggin.
Short Glossary of Medieval Clothing Terms: Doesn't supply links or pictures, but just definitions.
Fiber and Needle Guild: Tailoring: Links to all sorts of costuming sites.
Garb Patterns: More links. Many are dead, but a few are extant.
Greek Dress: Peplos and chiton.
Naalbinding tutorial: Video is not in English, but I could still follow along.
Historiska världars dräkter: Guess what? Not in English! But has full outfits (head to toe) of a variety of historical garbs. Includes 2 male Viking outfits, and one female. Patterns are included.
Othalacraft: A shop that sells all sorts of lovely Viking clothing. No patterns, but lots of inspiration.
Raymond's Quiet Press Historical Recreations from Jewellery to Helms: What it says! Lots of reproduction metal work. Covers Romans, Vikings, Celts, Romano-British, Normans, and more.
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Botswana’s metal fans are perfecting the Thunderdome chic: And now for something completely different.
Making a Miniature Book: Ok, not costuming, but it is prop creation, which is related, in my opinion.