Noticed some green in the empty lot next door & just finished digging up about 200 Lycoris radiata bulbs. Also found several clumps totaling about 100 bulbs of unknown Allium species, a couple smaller clumps of daffs and a lone Gladiolus.
If your grass has gone dormant and you live in the south in an older (or just a non-housing-development) neighborhood, there's a good chance you could find some bulbs, just as long as it's OK for you to dig them up. They're very distinct in this area right now.