Need to add:
FL 399 (this only consists of 1/3 mi of the route between US 98 and just short of the bridge to the barrier island, the rest being CR 399, but it is signed)
That one is debatable. Normally, for us to consider the route as 'signed', there needs to be at least a shield on the mainline (couldn't find one). So this one might not make the cut.
That's funny. I actually had that same thought (debatable) in my original post, but must've removed it while I was editing it.
A few more thoughts from 600-802:
FL600/FL600tam: delete, all hidden
FL615: remove BellAve, route starts at CR611
FL620: add (the first two waypoints of FL655 are actually FL620)
FL651: delete, unsigned (already mentioned)
FL655: see FL620
FL683: delete, unsigned portion of US301 (already mentioned)
FL685: trim to first two waypoints only. Beyond there is not signed. (already mentioned)
FL700: Keep standalone piece in Palm Beach Co, Old Connors Rd/Main St. Technically beyond Canal Point to Okeechobee it's also signed occasionally (as is FL 15)
along with their US highway companions but since FL015 doesn't go past Canal Point in the usafl system I'd say do the same with FL700. Delete all the rest of FL700 as it's hidden under US98.
FL700Bro: Keep
FL707. This one is weird. On the delete side: It's not in the FLDOT shapefiles. And it's signed as CR707 in downtown Stuart. However, in the streetview, there are multiple FL 707 shields north of the drawbridge up to "TO US 1"/NW Wright Blvd.
FL739: Extend south to Alico Rd/US 41 interchange. Delete north of FL80, becomes hidden under US41Bus.
FL750: The route was extended west from FL291 to US29, and that's what's in the shapefiles. However, there is currently no FL750 signage that I could find west of FL291, including with the interchange with I-110.
Just my 2ยข. --Joe