Relying on monster drops for flax fibers is a sure way to not get too many. Yew branches for pale, lebethron for yellow, black ash for gold. Yew branches are prevalent in eastern Lonelands, eastern North Downs, and Evendim. Lebethron is in Trollshaws and Angmar, and parts of Evendim. Black ash in Misties and Eregion. Humanoid monsters in those areas drop the respective flaxes, but very rarely.
And if they're not too expensive, the AH may have some for you. Also another alternative is the skirmish crafting vendor, for marks (not sure what the rates are now).
To many people, free will is a license to rebel not against what is unjust or hard in life but against what is best for them and true.
Actually, the best way to get flax now is, IMO, by skirmishing. They actually lowered the optional crit ingredient barter costs in U5. See the first link in my sig for the Google docs that detail how many flax (at cap) you can get per skirmish. Of course, the direct barter numbers will be lower if you don't have a capped toon.
well poop. i have a boat load of the prior optional items. i quit for a few years. ok thanks ya!
If you mean the old crit items, you can exchange them for the new types. I think there is an exchange NPC at the crafting hall in Bree, pretty sure there is also one in the Michel Delving crafting area.