izigame.me

This is my favourite minor DLC for civ 6. I play civ 7 now, but I really wish there was a DLC like this for civ 7. Firstly, Vietnam is very good. It's ability presents difficulties by not allowing one to place districts on most tiles. However, the increased culture, science and production can be extremely beneficial. Since the Vietnamese leader's ability also provides bonuses in marsh, rainforest and woods, if you start a game as Vietnam and don't start in an area with lots of those features, it's advisable to restart the game. Also, the music for Vietnam is very good. In the early eras, basic and early instruments play the theme, which develops into an orchestral masterpiece as the eras go on.
In my opinion, Kublai Khan is an average leader. I haven't played as him much, and, when doing so, didn't particularly enjoy it.
Vietnam aside, the main reason I'm recommending this is for the game mode: Monopolies and Cooperations, and the new district: the preserve. These are what I wish there was in Civilization VII. I may not play civ 6 anymore, but if I come back to it, and when I did play it, I did always and will always use the Monopolies and Cooperations game mode (even though the names for products can be a bit weird.) The preserve encourages you to not improve tiles, and gives great benefits, benefits that outweigh the benefits of improving them, for not doing so. There is no downside to building buildings or improving tiles in civ 7. You just get the yields. The adjacency bonuses in civ 7 already make building and improvement placement very interesting, but a building like the preserve could greatly enhance those mechanics.
After getting Gathering Storm, this was the first minor DLC I got, before getting Anthology when the leader pass came out. I highly recommend this, to those of you who still play civ 6.