The gold 1-2 star Champions listed below currently boast an incredibly high chance of securing a top 4 finish.
Euphoria (Main Champion Core of Jinx)
Following the overhaul in patch 13.3, upgrading Euphoria has become significantly more potent than before. This Champion Core empowers Jinx to become an exceptionally strong centerpiece in the Super Beast composition with the ability to rapidly accumulate Fame. As a result, the top 4 placement rate of the Euphoria core is currently at a very high threshold of 59.7% (statistics from Tactics.tool).

To fully utilize this upgrade, players should equip Jinx with Shojin Spear and Statikk Shiv. These items will help Jinx cast her ultimate more frequently, causing opponents to stagger and dealing a considerable amount of damage. This upgrade holds significant value in the early and mid-game if players have Jinx and the Super Beast framework.
Empire of Fury (Main Champion Core of Renekton)
For many gamers, Renekton is simply seen as a tanky unit in the Duelist or Laser Vanguard compositions. However, Chinese pros have discovered a way to turn Renekton into a formidable powerhouse with the Empire of Fury core. Moreover, this upgrade boasts a top 4 placement rate of up to 58.7% (statistics from Tactics.tool).

With Renekton's Empire of Fury, players will need to equip two 'defensive' items: Bloodthirster and Giant Slayer for this unit. These items will increase Renekton's durability and healing capability. As for attack speed, the Empire of Fury core has already provided significant stats in this regard. Players should refrain from equipping Guinsoo's Rageblade or Titanic Hydra for Renekton.
Laser Sight (Main Champion Core of Ashe)
Despite not being selected frequently, the top 4 placement rate of the Laser Sight core is extremely high. According to statistics from Tactics.tool, this upgrade has a staggering 58.6% top 4 placement rate at the current time. With this upgrade, Ashe becomes an incredibly potent powerhouse with both damage output and attack speed stats.

As a 1-cost unit, Ashe with the Laser Sight core will help players achieve a fairly long winning streak in the early game. This only stops when players enter the Shop rotation and upgrade Ashe to 3 stars. After successfully upgrading Ashe, she will transform into a very strong powerhouse and regain the winning streak for the gamer.
Conclusion
By nature, as the cores of 1-2 cost champions, players can obtain upgrades like Euphoria, Empire of Fury, and Laser Sight right at the beginning of the match. This enables them to achieve superior power levels and secure victories through snowballing. These upgrades promise to be highly suitable for players accustomed to maintaining winning streaks.