Yangzhou Mahjong requires minimum points to win and scores based on hand patterns. If you play Riichi or MCR, this will feel structurally familiar, but the specific patterns are all Jiangsu.
Nanning Mahjong adds a fishing mechanic on top of standard play. Simple rules, but the Lucky Catch keeps every hand unpredictable in a way that makes you want to play another round.
If you want the simplest possible entry into Chinese regional mahjong, it might be Hebei. No winning restrictions, straightforward scoring. Just build your hand and win.
Fuzhou Mahjong deals 16 tiles, has a Gold wildcard tile (金), and the scoring is simple enough to pick up in one session. One of the friendliest entry points into Chinese regional variants.
Guiyang Mahjong has Chicken tiles and Beans. Not the same Chickens as Singaporean Mahjong. Different animal, different mechanic. Guizhou Province built its own thing here.
At the start of your hand in Changchun Mahjong, you get a chance to form a special Kong, laid face down like a lucky egg. One mechanic, and it changes your entire opening.