The next TFT champion that will be likely coming to the game in the 9.17 patch will be Pantheon! He is a 5-cost Dragon/Guardian unit and has a pretty crazy ability that has him turn into or ride a dragon into battle that decimates any enemies that stand in his way. Here's a look at the animation:
Pantheon + Teamfight Tactics
— League of Legends (@LeagueOfLegends) August 15, 2019
The ability is called "Grand Starfall" and it currently reads, "Pantheon leaps into the air and then crashes down on the furthest enemy, stunning it and dealing % max health damage to everything on the way." It's still in early testing as far as we know, so things could change before the release. If you're in the PBE (Public Beta Environment) you can try him right now! For everyone else, he will likely be included with 9.17 patch that should be launching on Wednesday, August 28, 2019.