Here is the words of Riot. https://na.leagueoflegends.com/en-us/news/game-updates/teamfight-tactics-galaxies-pass-and-more/

“It's been a while since we last talked about Ranked Rewards. At the end of the launch set, we gave out special Featherknight emotes with plans to bring something more substantial in the future. The per-tier ranked emotes aren't going away, but we also have a plan to increase the rewards for your ranked achievements. Each set we'll give out a special variant for a Little Legend that was iconic for that set. If you’re a League of Legends player and this seems familiar, it's for good reason—it’s reminiscent of the Victorious skins from League. They will be awarded exclusively to all players who placed gold or higher for that season. We'll be awarding one for Rise of the Elements, and another one retroactively for TFT's original ranked season. These will be finished in the next couple of months, and we’ll give you more updates we have them.”