The following Team Compositions in Teamfight Tactics are highly favored by Riot Games in the current patch.
Divine Child
Despite Riot Games' intention to tone down the power level of 5-Star Divine Children, they inadvertently bolstered this Team Composition in Patch 13.9. Specifically, Riot has increased both the damage output and resilience of Divine Children at the 3-champion threshold. This enhancement fortifies the Divine Child lineup considerably at the early stages of the game, providing ample health and economic resources to pivot towards the centerpiece, Gnar.

The additional damage amplification synergizes remarkably well with Gnar. Consequently, Gnar can inflict substantial damage from the early game instead of relying solely on reaching the 3-star level. Naturally, Gnar's late-game prowess may be slightly diminished, but the pace at which this Team Composition navigates through Teamfight Tactics is significantly improved.
Double Duel
Similarly to the Divine Child lineup, Double Duel has also received a slight power boost in the early game phase. Specifically, the two 1-gold champions, Kayle and Gangplank, will have increased skill damage and attack speed. With just such minor adjustments, Double Duel can rise strongly in Teamfight Tactics.

In essence, Double Duel has been a strong lineup since previous patches with many high-quality carries. In Patch 13.9, the early game strength of this lineup has been enhanced, and its ability to sustain has improved. This is a fantastic condition for Teamfight Tactics players to aim for Vayne or Twisted Fate with ample equipment late game.
Ox Warrior - Twisted Fate
With the Protector being significantly weakened in Patch 13.9, Teamfight Tactics players are forced to seek alternative choices in the front line. And Ox Warrior emerges as a solid option with its powerful shield creation ability. This sets up favorable conditions for carries like Twisted Fate or Neeko to deal damage.

The biggest weakness of this lineup lies in the lack of healing reduction when Annie isn't a particularly strong Inferno Keeper. Teamfight Tactics players should address this issue by equipping Morellonomicon on Neeko to apply widespread healing reduction.
Conclusion
With significant power buffs in patch 13.9, the teams of Divine Child, Double Duel, and Ox Warrior - Twisted Fate appear quite formidable at the current moment. These promise to be incredibly effective climbing strategies in the newly released patch 13.9.
