You could always make some brine your self.

I preserve my own olives and after I remove them from the mother brine
(wich is just 10% cooking salt) I place them in a brine-vinegar
mixtu-

To a 1 litre measuring jug add 100gm of cooking salt, then add 500mL of
boiling water, stir to dissolve the salt. Allow to cool. Once cool add
100 - 150mL of cider or white wine vinegar, mix well then add water to
make the whole lot up to 1L in volume.

With my green olives I sometimes add a couple of cloves of garlic and a
couple of hot chillis then add the brine-vinegar mix.

Sorry about the metric measurements but Australia moved over to the
metric system some years ago and coupled with the fact that I have been
working in Science for over 30 years I tend not to use Imperial/US
measures much.