Number 20: Giga-Brilliant

Level 3 LIGHT/Insect Xyz Effect
1800 ATK / 1800 DEF

2 Level 3 monsters
Once per turn: You can detach 1 Xyz Material from this card; all face-up monsters you currently control gain 300 ATK.

Rulings – Yugipedia

Printings:

Photon Shockwave: PHSW-EN042 (Super Rare) - 2011-11-10
Zexal Collection Tin: ZTIN-ENV02 (Ultimate Rare) - 2013-03-07
Battle Pack 3: Monster League: BP03-EN119 (Shatterfoil Rare) - 2014-07-31
2-Player Starter Set: STAX-EN042 (Ultra Rare) - 2024-01-26

Prices:

Cardmarket: 0.15 €
TCGplayer: $ 0.28