THCV shows up in noticeable amounts in certain African sativa lines, particularly Durban and some Malawi and Swazi stock, and it is one reason those genetics feel different from a Colombian or Thai plant. It is present at low levels in most cannabis but a few of these lines test well above the usual trace amounts. The cannabinoid profile notes on https://hazesativaseeds.com flag which of their African lines have tested for it and how much variation there is between phenotypes from one pack. Breeders are starting to select for it, which makes those packs worth watching.