Yuumi
No matter the season of Teamfight Tactics, crowd control effects are crucial for players to secure victory. If you can control the damage dealers or tanks of your opponents, your chances of winning increase significantly as you reduce the amount of damage your team receives. Therefore, it’s no surprise that a champion with powerful crowd control abilities like Yuumi, even at 1-star, is highly favored.

In addition to crowd control, the shields that Yuumi provides when attached to allies are also incredibly strong in both offensive and defensive aspects. With high-speed carries, they help Yuumi “charge” energy much faster. Meanwhile, in terms of defense, the shields from Yuumi also help that unit rarely get “one-shot” by Assassins. With so many benefits, Yuumi consistently brings a lot of strength to your team composition.
Tahm Kench
It’s not an exaggeration to say that 90% of Tahm Kench’s power doesn’t come from his tribe or system, but rather from his ability, Devour. Gaining a bit of health and gold from the Brawler or Mercenary tribes is nice, but it pales in comparison to the limitless power growth that comes from feeding Tahm Kench. As long as you feed this unit the right champion and achieve reasonable stats, Tahm Kench can possess incredibly strong tanking abilities without needing to activate any tribe or system bonuses.

Moreover, when Tahm Kench uses Devour and takes down an opponent, this unit also provides you with a significant amount of gold or valuable items. The added gold will give you more opportunities to acquire and upgrade important units. Meanwhile, items are an incredibly valuable resource in the late game when you reach item limits. Therefore, if you need a frontline unit that has good survivability, strong damage, and solid “gold hacking” capabilities, Tahm Kench is the best choice.
Jayce
Although designed to be a flexible unit, we have to acknowledge that Jayce is much stronger in melee form than in ranged form. The reason is that Jayce in melee possesses both offensive and defensive capabilities that the ranged form lacks. With a skill effect that reduces up to 50% armor/magic resistance at 1-star and 2-star, melee Jayce can amplify the total damage dealt by the entire team to an immense level.

Furthermore, this unit is not picky about items and can hold full defensive gear while still dealing incredible damage in melee form. Therefore, in almost every match, you can use Jayce in the frontline, possessing a unit that is both “tanky” and has high damage output. Remember that in the late game, your carries usually have full items, and Jayce’s armor/magic resistance reduction effect is incredibly valuable in finishing off the match.