WordNet records no synonym and no antonym for quota. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
a prescribed number
“all the salesmen met their quota for the month”
a proportional share assigned to each participant
a limitation on imports
“the quota for Japanese imports was negotiated”
Synonyms, antonyms and the broader and narrower relations for quota come from Princeton University’s WordNet. Full sources and licences.