Is 'Anythings' Correct?
There is no such word as 'anythings' in standard English. So, if you want to use 'things' as in plural, then you need to use 'any things' (with a space between 'any' and 'thing). For example:
'Anything left on the garbage will be cats' food', is also correct.
'Anything' is an indefinite pronoun that is used to refer to something unspecific or unknown. It can be anything at all (it doesn't matter what). It is mostly used in questions and negative sentences.
Never use 'anythings'. It's wrong in every contexts.
Use either 'Anything' as a singular indefinite pronoun,
Use 'any things' as a noun phrase to refer to several objects.