How red flags and best bets work
Red flags are measured from each parcel's boundary on the county parcel map: road frontage from U.S. Census road lines, wetlands from the U.S. Fish & Wildlife Service, flood zones from FEMA. They're screening estimates, not a survey. "No road frontage" can mean a private road or easement the maps don't show.
Best bets are properties with an upcoming sale (or forfeited land you can still buy) and clean land: no serious red flags, at least 25 ft of road frontage, under 10% wetlands, not mostly in a high-risk flood zone, and at least 0.1 acre. Where the county lists an appraised value, it must be at least 5 times the taxes owed. The top 25 in your current view are shown, ranked by appraised value compared with taxes owed, then by size. A very high ratio also means the owner can easily pay, so many of these will be redeemed or bid up. Treat them as a starting point, not a prediction.