The question I saw referred to over a 30 year period. All of these schools had some good runs, but Battlefield has only been around for about 8 years, 8 real good years, I grant you.
Gar-Field hasn't made a final 4 in 24 years, and actually only advanced past the round of 8 twice (1977 and 1990). A decent program, but not the kind of run that makes you dynasty.
Woodbridge Similarly has only made two final fours (1974 and 2007). They are kind of a perennial early exit team.
Deep Creek has only advanced beyond the first round of the playoffs a handful of times (1994, 1995, 2000, 2001)
From 1970-2007 Lake Taylor only had one season where they won a playoff game. So while they are having a great run, they are still short of being a high school dynasty by a decade or so.
Potomac had a good period from 86-90, but then they missed the playoffs six years in a row. Hard to see enough playoff runs close together to consider them one.
Glass had a nice little run from 71-76 and then again from 86-95, so they had two mini-dynasties.
Pulaski's run from 1982-2001 definitely is one of the more impressive in VHSL history. They've fallen off since then, but still it is a nice run.
Gretna's 11 year run was impressive (2001-2011) especially considering where they'd been, but over the 45 years of VHSL football playoffs, 11 years is one of the longer runs of greatness.
I haven't read the whole thread, but Graham is one I didn't mention, but should have. Real nice run from 1989-2009.