I don't want to appear overly critical of re-enactors, especially as that's my own group in the photos… however my background is in archaeological conservation where I once shared a laboratory with one of the worlds leading experts on early medieval textiles and dye analysis and now make part of my living supplying replica Viking/Saxon textiles to museums which I hope gives me a little authority to speak on the subject.
Individual reenactors look for bits of evidence or reasons to justify doing what they personally think looks cool which is not the same as a whole society studying all the evidence to establish and give a balanced portrayal of what was common or representative of the period.
All the evidence we have points to the fact that by far the most common amongst most folk, numerically dominating everything, was undyed wools in natural pale greys and browns, which is why odd scraps of literary evidence from the period imply "coloured" clothing was so rare without actually seeing the need to distinguish between different colours. Any mention of coloured clothing is used to instantly establish the rich or significant people from the mainstream masses.
In terms of dyes that survive in the archeological record to be detectable today madder reds are the most common in England (which with a weak or poor dye batch gives salmon pinks and pale oranges, all of which soon fade in the sun), In Norway woad blues are the most commonly detected, in Ireland lichen purples are the most commonly detected whilst in Denmark evidence suggests they seemed to favour over-dying things to create darker "blacks".
However we must be aware that the archaeological textile samples proving positive in dyes tests are so out numbered by those showing no evidence of dying that trying to say anything meaningful about different colours is merely speculating within statistical rounding errors.
A simple analogy would be to say that if talking about different Formula One motor racing cars you may not mention that most ordinary folk don't drive one but own a second hand hatchback.
The flip side of the argument is how few natural dyes survive the burial environment to be detectable in the present day, where most easily accessible plant based dyes give weak yellowy greens, save for weld which gives a lurid (high visibility security vest) yellow.
You can speculate and say that because onion skins give orangey brown colours and onions were probably common food stuffs they must have been commonly used for dying… truth is there is absolutely no way of verifying if it is a correct assumption.