Landrace strains are essentially the ancestors to EVERY single cannabis strain on the face of the earth. They are the original cannabis strains collected by our ancestors thousands of years ago. Some of them are still available today, and it is always nice to pay tribute to the forefathers of the 3000 or so strains currently tracked by Leafly.
There is of course some debate as to how many there are and their origins, but it seems "sativas" came from temperate regions, while "indicas" came from the more mountainous regions of the world. They are important because they literally "gave birth" to the modern cannabis industry. These articles from Leafly True Terpenes, and The Vault give a nice introduction.
Here's an alphabetical "long" list of Landrace Strains. Those in bold are rarely debated as worthy of this list.Acapulco Gold
Mazar I Sharif