The Reserve (in Henderson) has new owners (Station Casinos), so those chips will be retired when it changes names.

The Aladdin's financial status is tenuous, so it's always possible that new owners might replace the current Aladdin and/or London Club chips. (Though I personally hope they make it.)

The Regency (in Summerlin) is in bankruptcy and the judge is accepting competing bids from prospective new owners. May take a while, but eventually new chips required.

Imperial Palace owner, Ralph Engelstad, announced at one time that he planned to sell the IP when he retires. Nothing imminent as far as I know, however.

Fiesta (NLV) sold to Stations Casinos 5-6 months ago, but hasn't changed chips so far. Will they? Don't know.

Speedway Casino never has any business when I'm in it, though the owner keeps it running, along with it's counterpart Speakeasy Casino in Reno. Maybe pick up a few of these, on the come, in case an unexpected closure?

That's a few places to consider for your next chip run.