Walmart has the Neon Red and Neon Blue Controllers on sale right now.
https://www.walmart.com/ip/Nintendo-Switch-Joy-Con-Pair-Neon-Red-and-Neon-Blue/55449978?u1=&oid=223073.1&wmlspartner=AKGBlS8SPlM&sourceid=39967288133737335404&affillinktype=10&veh=aff
These have been almost as hard to find...
I received a notification from istocknow of a neon switch at Gamestop just last week (Southern California). I called the location and they actually had the switch, but it was fcfs. I'm not sure how that Gamestop had the switch; it might have been a return. Still, your best bet besides calling...