A variety of omens? Start worrying! (10)
I believe the answer is:
assortment
'a variety' is the definition.
('assortment' can be a synonym of 'variety')
'omens? start worrying' is the wordplay.
'worrying' is an anagram indicator.
'omens'+'start'='omensstart'
'omensstart' with letters rearranged gives 'ASSORTMENT'.
'of' is the link.
(Other definitions for assortment that I've seen before include "Variety" , "Miscellany" , "Mixture" , "Medley" , "Miscellaneous collection" .)