My hero is a composition of all those who despite knowing that a situation would be dangerous or fatal for them, still got up and did it, and our carers and emergency services, service personel and individuals.
Every stabbed, shot, fatally dragged police officer, every brave fighter pilot or soldier in the trenches, or waiting to drop into an unwinnable zone. Every Doctor knowing their PPE isn't the right type, or sufficient, or too old to be fully safe, just getting on with it. First Aiders and MO's stabilising the wounded while still under fire. Pilots steadying a dying aircraft so their crewmates can bail out.
Too many heroes to mention sadly
As for notable heroes, I would love to have been Peter Sellers or John Lennon.