Perennial herbs are generally the #1 category of edible plant I recommend people grow in terms of value for money/effort. With a balcony that gets decent sun you can grow heaps in pots. Rosemary is a no brainer, thyme and oregano are strong contenders too. As is mint, in a cooler spot.

As for annuals and biannuals, I’m a big fan of parsley and chives as being very easy to grow. Coriander more so in the cooler months.

And basil in summer - extra delicious, cheap, plentiful and great for making excess pesto to freeze and use over winter.