Please format your code so it's not single-line: /blogs/dan_patterson/2016/08/14/script-formatting
selectList = []
fip = '13245'
for fc in featureclasses:
select = arcpy.MakeFeatureLayer_management(fc, "temp_lyr","FIPS_CODE = '{}'".format(fip))
arcpy.env.workspace = "C:/Workspace/Sandbox/selects.gdb"
selectFeatures = arcpy.CopyFeatures_management(select, "select_{}".format(fip))
selectList.append(selectFeatures)
See here for using geoprocessing result objects: Using tools in Python—Help | ArcGIS Desktop
I'm guessing you want to use:
selectList.append(selectFeatures[0])
selectList.append(selectFeatures.getOutput())