Check out the wiki page on crops:
https://dwarffortresswiki.org/index.php/DF2014:CropSurface crops are nice and simple because they grow year round.
Which surface crops appear and can be grown will depend on your biome, but there are several that produce thread (cotton, rope reeds, hemp, flax, jute, ramie, kenaf), and some of those produce other products. Rope reed, notably, produces booze and thread. Hemp, flax, cotton, and kenaf produce thread, flour and paper.
For simplicity, start with gathering crops that are growing around your embark. One easy way to keep seeds in stock is to forbid cooking any brewable plant in the kitchen settings.
Processing to flour produces seeds, so that's a good way to get food for meals without much micromanagement. (longland grass, whip vines, all the wheats/spelt/barley/oats/rye/rice/quinoa/milet/gasp/etc) all make flour, and most also make booze, so can supply both needs.
In general, a small number of farm plots supports a very large number of dwarves and your problem will rapidly become having too much food/booze and no containers/space to store it.
Several crops are bugged and don't produce seeds, but if you just gather a bunch of plants, grow, and process them, the ones without seeds will rapidly vanish, leaving you with an abundance of renewable crops. The basic
Modest Mod (without any of the optional modules) fixes most plants.