More than plentiful evidence of embroidery skill (7)
I believe the answer is:
sampler
'more' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'than plentiful evidence of embroidery skill' is the wordplay.
I cannot really see how this works, but
'plentiful' could be 'ample' ('ample' can be a synonym of 'plentiful') and 'ample' is present in the answer.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for sampler that I've seen before include "Maybe daughter's work" , "Taster - piece of embroidery" , "Sewing practice piece" , "Piece of embroidery done as exercise" , "Embroidered specimen piece" .)