VHSL-Reference's records go back to 1999, hence the rather arbitrary date for this:
Teams with most seasons with 10 or more wins since 1999
13 L.C. Bird
12 Stone Bridge
12 Phoebus
11 Oscar Smith
10 Salem
10 C.D. Hylton
10 Gretna
9 Giles
9 Essex
9 Riverheads
9 Westfield
9 Gate City
9 Powhatan
Teams with most undefeated regular seasons since 1999
7 Salem
7 Phoebus
6 L.C. Bird
6 Oscar Smith
6 Westfield
6 Hermitage
6 Stone Bridge
6 C.D. Hylton
5 Ocean Lakes
5 Essex
5 Gate City
5 Gretna
Most wins since 1999
186 Phoebus
168 L.C. Bird
167 Salem
165 Oscar Smith
159 Riverheads
157 Gretna
155 Stone Bridge
154 Hampton
153 C.D. Hylton
152 Essex
Best winning pct. since 1999
.894 Phoebus
.857 L.C. Bird
.852 Stone Bridge
.846 Oscar Smith
.827 Salem
.824 Riverheads
.810 C.D. Hylton
.809 Westfield
.805 Gretna
.802 Hampton
Teams with most seasons with 10 or more wins since 1999
13 L.C. Bird
12 Stone Bridge
12 Phoebus
11 Oscar Smith
10 Salem
10 C.D. Hylton
10 Gretna
9 Giles
9 Essex
9 Riverheads
9 Westfield
9 Gate City
9 Powhatan
Teams with most undefeated regular seasons since 1999
7 Salem
7 Phoebus
6 L.C. Bird
6 Oscar Smith
6 Westfield
6 Hermitage
6 Stone Bridge
6 C.D. Hylton
5 Ocean Lakes
5 Essex
5 Gate City
5 Gretna
Most wins since 1999
186 Phoebus
168 L.C. Bird
167 Salem
165 Oscar Smith
159 Riverheads
157 Gretna
155 Stone Bridge
154 Hampton
153 C.D. Hylton
152 Essex
Best winning pct. since 1999
.894 Phoebus
.857 L.C. Bird
.852 Stone Bridge
.846 Oscar Smith
.827 Salem
.824 Riverheads
.810 C.D. Hylton
.809 Westfield
.805 Gretna
.802 Hampton