Over the course of several months from May 2020 through April 2021, nine new leaders and eight new civilizations were added as part of the New Frontier Pass. In addition, two Persona Packs were added in July 2020.
Eight of the new leaders came with their new civilizations, but the ninth, Kublai Khan, was added as a second leader option for either China or Mongolia.
In the Persona Packs, the developers introduced two new options each for Theodore Roosevelt and Catherine de Medici. Roosevelt becomes either Teddy Bull Moose or Teddy Rough Rider, and Catherine becomes either Black Queen or Magnificence. Unless one plays with the original (Standard Rules) version of Civ VI (not Rise and Fall or Gathering Storm expansions), these personas replace the original Teddy and Catherine.
A full outline of the New Frontier Pass expansion, including a listing of the new civs and leaders, is available at the Civilization Wiki website, a site I highly recommend for all kinds of detailed information about the game.
As I mentioned in the previous post, I have played and won at least five games with each of these leaders. Some unique attributes make them all interesting to play, and some even feel over-powered at times. Although I’ve enjoyed them all as I played them, I cannot say any of them have become real favorites yet. I think it will take more intentionally playing to exploit their attributes than I did so far. I tend to play a style that favors diplomacy and not all of the new leaders or personas are as well suited to that as they might be to another focus.
For anyone who is interested in a detailed analysis of Civ VI leaders and suggestions for how to play with or against a particular leader, I recommend the excellent Zigzagzigal’s guides found on Steam.