Synonyms for Cull:

n.

separate, stockpile, assemble, buy up, winnow, scrape together, get together. capture, glean, amass, bait, cast, bite, angling, big game, collect, accumulate, harvest, round up, blood sports. destroy, hunt, single, hunt out, choice, put down, exterminate, opt, butcher, bag, poach. garner, extract, pick up, gather.

v.

contact (verb)
pluck, pick.
diminish (verb)
diminish, decrement, concentrate, truncate, abridge, shrink, lessen, prune, contract, weed, reduce, compress, downgrade, minimize, compact, decrease, abbreviate, trim, taper, shave, shorten, deflate, dwindle, condense, erode, pare, lighten, bob, deplete, nip.
gather (verb)
collect, amass, round up, garner, accumulate, pick up.
pick out for reason (verb)
glean, extract, winnow, pluck.

Other synonyms:

opt, glean, scrape together, stockpile, assemble, hunt out. get together, hunt, accumulate, exterminate, poach, round up, garner. destroy, extract, collect. butcher. gather. bag. put down. single. choose
winnow, opt.
pull
weed.
Other relevant words:
gather, glean, extract, poach, get together, garner, opt, harvest, pick, amass, assemble, choice, collect, winnow, stockpile, accumulate, pluck, hunt, scrape together, bag, destroy, exterminate, single, separate.