Chrome Rares are a new rarity first introduced in First Edition boxes of Heroes Clash.  They are individually numbered from 1 to 100 and there are only ever going to be 100 copies of each Chrome Rare. 

There are multiple unique Chrome Rares in the set. Each one is a Character card from the corresponding set. 

The five characters in Heroes Clash are: 

Ejiro Kirishima 1

Izuku Midoriya 2

Katsuki Bakugo 2

Shoto Todoroki 1

Tenya Iida 3

The five characters in Jet Burn are:

Dabi 3

Endeavor 3

Hawks 1

Izuku Midoriya 5

Katsuki Bakugo 4

The four characters in Dark Tournament are:

Hiei, Dragon Within

Kurama, Youko Unleashed

Kuwabara, Spirited Warrior

Yusuke, Team Leader