Not even one link with open slather for weird things (8)
I believe the answer is:
oddities
'for weird things' is the definition.
(I've seen this in another clue)
'not even one link with open' is the wordplay.
'not even' becomes 'odd' ('odd' is the opposite to 'even').
'one' becomes 'I' (Roman numeral).
'link' becomes 'tie' (synonyms).
'with open' becomes 's' (I can't explain this - if you can you should believe this answer much more).
'odd'+'i'+'tie'+'s'='ODDITIES'
'slather' acts as a link.
This may not be right. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for oddities that I've seen before include "Eccentric things or people" , "Peculiarities" , "Tidied so as to suit unusual things" , "Quirks" , "So tidied up for strange people or things" .)