The opposite of "-siz" is "-li".
Containing Condition: [meaning: furnished with, containing, belonging to, place of]
Suffix -li/-lı/-lu/-lü gives the sense of belonging to somewhere or being contained in something.
It equates to with [with sugar] and various "additional and augmenting" suffixes and prefixes in English.
[leafy, salty, coloured, numbered]
Without (lacking) Condition: [meaning: without]
Suffix -siz/-sız/-suz/-süz. This suffix gives the sense of lacking.
This suffix equates to without [without sugar] and the various negating prefixes and suffixes of English un- dis- non- -less
[unfair, dishonest, nonsense, hopeless]
There is also -le
With Condition: [meaning: together with, and, also]
Suffix -le/-la or -yle/-yla after vowels.
This suffix can also stand alone as a separate word ile.
Refer to http://www.turkishlanguage.co.uk/suffix.htm
"var" is not a suffix.
The opposite of "var" is "yok"
Refer to http://www.turkishlanguage.co.uk/varyok.htm