The greenish one on the left is Regia Pairfect in "Lagune" colourway. I've made several pairs of socks from Regia (including the purple/blue/jade/brown stripy pair currently in progress) but the Pairfect is a little different ... that bright yellow bit you can see is repeated again halfway through the skein but is not intended to be knitted; instead the yellow marks the starting points to end up with two identically patterned socks. The other two skeins are Opal, which I've not used before but is legendary as a European workhorse sock yarn and the first to pioneer built in colour patterning/striping. The blue/purple in the middle is Opal Classics in "Anmutig" colourway and the multicoloured on the right is Opal Nach Hundertwassers Werk in "Garten ohne Grund" colourway (painting that inspired the colours is on the label)
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