It's all pretty random tbh.
he can't stand anything with a perfume for a start.
As for materials, it's hard to say as it's difficult to separate the material from the colour iyswim?
He has some fleece tops that are fine - some colours are better than others even though they are the same brand and garment type. He has some red ones that are pretty good and a green one that is okay but he can't wear the blue. so they are manmade fibre.
Of the t-shirts that he can wear, he has some dri-fit type that are fine including some blue ones.
The best ones though are egyptian cotton and natural dyes. Green, natural, grey and pale bluey grey. He cant wear the black, white or red.
He has a softshell jacket that he can wear (black) so we ordered another one even though it was £150 so that he can put it away as it's rare that he gets a jacket he can wear.
We ccan only use surcare powder - even the liquid isn't any good and he can only wash with plain soap bars - even his hair.
If he puts on something he can't tolerate, he goes numb down one side, his face gets a rash and swells in a band across his nose and cheeks, he gets massive headaches and his hair itches, the side that goes numb loses colour so he has one one normal looking hand and the other pure white if you leave it then he gets chest pains and struggles to breath :(
This came on suddenly about 8 years ago and despite brain scans and allergy tests and paying privately for a consultant we have generally just had to manage it ourselves. The GP eventually suggested that it was all psychological so he just gets on with it now. The worst was when we bought a new car and found that he was allergic to the seats - he'd been fine in the demonstrator.
He is definitely not as bad as he was and can usually tell if something is unlikely to suit fairly instantly if it is likely that it will cause a more severe reaction. Sometimes though it just creeps up on him. He has a couple of shirts for going out in that he can tolerate for a few hours but we have an all day wedding coming up in October so that is going to pose a bit of an issue.
I find that if I stick to cheaper mixed fibre bedding and non white and just wash it a lot then we have been quite lucky.