Here is a Genshin Impact team guide article on how to build Thoma team comp including details of the team members and free-to-play team.
Thoma is a character whose both of his skill deal AoE Pyro DMG and creates a shield that can absorb DMG. Since he creates a shield to absorb DMG, he is a supporter of the team who provides a safe environment for the team.
Here is some team build that is suitable for her:
Thoma F2P - Vaporize Team Comp
This free-to-play team is a great option for a player who doesn't want to spend Primogem or a newbie who doesn't have any 5-star characters. Even though, this is a F2P team you still can maximize his potential as well. This team focuses on maximizing Vaporize reaction DMG by having Xiangling as the Main DPS to react with Xingqiu who can apply Hydro to attach enemies and Sucrose to provide grouping enemies as well as lower enemies RES.
- She is a Sub DPS who can apply hydro elements continuously attached to enemies using EM burst as well as provide some protection.
- Both of her elemental skills can apply Pyro AoE DMG even if the character is off the field. Her Pyronad will move with active character making it easier to combo with Xingqiu.
- Provide DMG buff to all allies, reduce EM resistance, and group up enemies which makes it easier to create a Vaporize reaction and Xiangling and Xingqiu to apply EM Burst easier.
Thoma Melt Team Comp
This team comp focuses on maximizing Melt DMG by using Rosaria and Xingqiu to create a Freeze reaction and Thoma to trigger a Melt reaction.
- Hu Tao
- She is one of the best Pyro DPS who can output massive Pyro AoE DMG to enemies with her burst. Using her burst with freezing will get additional DMG.
- He can apply Cryo DMG with a combination of Xingqiu bursts making it easier to apply close-range enemies.
Thoma Burgeon Team Comp
This team comp focuses on continuously creating Burgeon reactions by using Thoma Pyro to apply on Dendro core that is produced by Ayato and Nahida.
- He mostly deals DMG from his Normal ATK to convert to AoE Hydro DMG.
- Can mark enemies apply Hydro DMG to the marked opponents and deal AoE Hyro DMG with her burst.
- Apply Dendro DMG to a large number of opponents up to 8 enemies to trigger Dendro Cores with Yelan and Ayato.
Thoma Vaporize Team Comp
This team comp focuses on continuously creating vaporized reactions from Xingqiu's Hydro and Pyro from Hu Tao and Thoma.
- Provide DMG buff to all allies, reduce EM resistance, and group up enemies which makes it easier to create Electro Charge and Neuvillete to apply Charged ATK.
End of Best Thoma Team Comp.