Yu-Gi-Oh: 10 Most Powerful HERO Cards
1. Elemental HERO Stratos
There can be only one.
What sets Stratos above the rest if his longevity. First printed in the last days of GX, he was hard to get a hold of and yet still made his way to the Limited list for the potency of his effect. He's spent most of his life on the Forbidden list, meaning the HERO cards had to grow without the kingpin, but is now back at 3 and more dangerous than ever thanks to his compatriots growth in his absence.
His effect is well known; add a HERO to your hand from your deck OR destroy Spells/Traps for all your other HERO monsters whenever summoned. This isn't just once per turn either; if you can execute multiple Stratos summons you can execute his effect multiple times.
His true legacy stems from his errata; in first print Startos could pull Elemental or Destiny HERO cards, back when the two were still distinct archetypes, making him the first card to significantly unify their support (no one cares about you, D-Time). His text would be adjusted again to include Evil HERO cards, before just letting you use any and all HERO cards for his effects. Across all the HERO cards, no one is as splashable, no one is as effective, and no one is as deserving as Stratos.