In Teamfight Tactics, there are many ways to defeat a certain composition, even the current top meta compositions are no longer intimidating if you exploit their strengths and target their weaknesses.
Here are ways to counter the current top meta compositions:
Countering “Tanky” Compositions: 4 Mystics + 4 Vanguard or 4 Guardians

For compositions with too many defensive stats, one of the most effective counters is to use true damage. In Teamfight Tactics season 3, there are two popular and easy-to-use sources of true damage: Morello’s Tome and the Void trait. Among them, Vel’Koz will be the key champion of the Void trait, capable of wiping out full magic resistance teams with just one ability.
Countering Compositions with Gangplank

For compositions using Gangplank “the world” with an item combo like Guardian Angel, Sorcerer’s Hat, and Stone Gauntlet, the best thing you should do is prevent Gangplank from using his ability. This can be done in various ways such as using items like Swordbreaker, Silent Cloak, or champions like Lulu, Ezreal, or Rakan.

In case Gangplank can use his ability, you can arrange your formation so that champions are as spread out as possible. This will minimize the chances of the entire formation getting hit by Gangplank’s ability when he hasn’t upgraded to 8-cost.
Countering Compositions with Champions That Have AoE Skills
In the current meta, there are powerful champions that can wipe out the enemy team with just one skill, like Vel’Koz or Miss Fortune. However, their weakness is that they can be interrupted while using their abilities. Therefore, you can use champions that can apply hard crowd control to stop the two champions mentioned above. Alternatively, you can simply use Trap Claw on a champion in the middle line; once Vel’Koz or Miss Fortune hits that champion with their skill, they will be stunned and interrupted immediately.

Countering Compositions with “Darius the Lumberjack”

In this composition, the opponent will stack powerful items on Darius like Guardian Angel, Rabadon’s Deathcap, and Stone Gauntlet. Essentially, targets below 50% health will take double damage from Darius’s axe, making it nearly impossible to stop this champion from earning some gold thanks to his Pirate trait. However, as long as you interrupt Darius’s continuous axe hits, this composition is not very scary. The item you should use is Guardian Angel – which prevents Darius from executing targets with his ability from being refreshed because the target is resurrected.
Hyper Roll Composition

For Hyper Roll compositions that roll early to upgrade champions to 3 stars, the way to counter them is to use champions with high crowd control like Lulu. What you need is to try to get Lulu to 2 stars; at that point, one hex will disable up to 4 enemy champions, and in a Hyper Roll composition, most opponents only have 6 or 7 champions on the board, meaning Lulu can disable more than half of the enemy team.
Compositions that Attack the Enemy’s Backline

Many compositions use a strategy that attacks targets in the backline such as Blitzcrank, Irelia, Shaco, Vi,… preventing many players from safely protecting their carries. The most effective way is to let your carry… roam around instead of staying in the backline. Specifically, you can use Aurelion Sol in the Rebel composition; the damage and shields from Rebels will allow Aurelion Sol to freely move around and deal damage. Especially, this champion also counters strong crowd control champions like Ekko or Lulu, making it hard to turn the tide in the late game.