WordNet (r) 3.0 (2006):

come by
    v 1: visit informally and spontaneously; "We frequently drop by
         the neighbors' house for a cup of coffee" [syn: drop by,
         drop in, come by]
    2: obtain, especially accidentally [syn: come by, come into]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "come by":
   accept, acquire, admit, assume, bag, be seized of, call, capture,
   catch, come in for, come into, come over, contract, corral, derive,
   derive from, drag down, draw, draw from, drop in, earn,
   enter into possession, gain, get, harvest, have, have coming in,
   heir, inherit, look in, look up, make, net, obtain, pop in,
   procure, pull down, reap, receive, run in, sack, score, secure,
   see, step in, succeed to, take, take in, take on, take over, win