I'm really fond of flag suits (I think that literally the first superhero comic I ever read was captain Britain) so I have a few
Der Englander was active before WWII an supernaturally gifted actor and master of disguise he operated throughout Europe rescuing scientists artists and musicians from the Nazi programs
he's based on this movie Pimpernel Smith from 1941. Itself based on the scarlet Pimpernel
And gets his powers from a fragment of the lost scabbard of Excalibur.
the fragment is called the heart of Avalon it has two powers over time it enhances the holder making them to the peak of their natural abilities they go from merely good at something to great and from great to legendary the second is enhanced healing toughness and never bleeding out from a wound.
He was superseded by a modern hero with the same origin but different powers while the original got super acting the modern hero got super intuition/precognition
Then there is Britannia
She is the mystic bonding of the spirit of the British isles and a series of teenage girls (think promethea with British National character) there have been several bearers of the mantel since she was first summoned during the reign of Queen Victoria.
Notable versions where the gun toting military Britannia of the Falkland war and the leather jacketed cool Britannia of the late 90s. Her powers are the ability to make weapons and armour from gold and silver material summoned from thin air.
Some of the Bearers have created chariots motorcycles and even seemingly independently intelligent lions.
Lion heart, Lady Lion heart
Both created by the avalon project the UK’s crash WWII supersoldier program desperately trying to give the UK a fighting chance against a Nazi invasion. Lion heart was the only successful recipient of the full serum a badly wounded but highly trained commando.
The serum gave him superhuman strength and resilience welding a golden mace he was an excellent propaganda tool for the allies.
Lady Lionheart on the other hand was an accident exposed to a random Sample of the experimental serums.
she gained superhuman reflexes, enhanced senses and improved tactical cognition.
Combined with her already extensive training in martial arts she was the dagger to Lionhearts blunt instrument.
Lionheart II and Black Jack
Both of these heroes gained their powers from parents who had been experimental subjects for project Avalon (there were many more but these are the flag suits).
Lion heart II was the first public Avalon baby believed to be the son of Lion heart he operated through the 60s before the shocking discovery of his true parentage (Nazi super soldier Eisenfaust) broke him and he became the villain Blackheart in the 70s.
Black Jack was the son of a jamaican commonwealth soldier who survived the early trials of the avalon project and returned with the windrush his 4th child was the only one who got the full power of the avalon serum (several of his nieces and nephews have since manifested some abilities)
during the turbulent times for the Caribbean communities of London in the Late 70s and early eighties he donned a black and white version of the union jack and defended the community from neonazis organised crime and even the police.
He was eventually framed for a crime he did not commit and sentenced to life in jail. He was eventually released when the truth was revealed.
He used a settlement from the government to set up a Nightclub which became a neutral meeting place for London’s superpowered set.
Now in his 60s he is a member of the Tower Ravens the UKs covert operations Super team under the name Mr Cosh and poses as a super tech fence.
Promenade is technically a flag suit although it's the flag of Brighton and Hove County Council who sponsor her under the sanctioned extra normal talent program (she's a gate teleporter who uses assorted grenades and fighting sticks)
As is the Gent (the world's greatest accountant) although in his case it's the coat of arms of the City of London which he wears as a crest on his blazer and has weapons based on it a red holographic sword, shield and small dragon (actually a sophisticated AI assistant).