I'm at the last step for my python script where I need to select the tracts that did not get selected on my initial selection so I can make a contiguous polygon (Trade Area). So below you can see blue boxes that highlight tracts that were not part of the final selection. The tan area all tracts and the darker color is my selected tracts. The initial selection of tracts was done using points and some analysis so that it got the best tracts to use. However, I need to fill in the gaps for those lesser tracts that are completely surrounded by those selected tracts. I'm hoping for a simple solution as my knowledge base is kind of limited. Code is always appreciated. Here is my very basic select code but the rest of it is very complicated at least for me.
arcpy.SelectLayerByLocation_management("Tracts", "INTERSECT", "AR_2021_XYTableToPoint selection")
## Now need to select those surrounded tracts.