The Tornado kick is the first cheat kick and vert kick that a beginner will learn - it forms the basis for learning the cheat setup. Learning a solid tornado kick works all the fundamental skills needed in tricking. From learning a takeoff off of one foot, using all the whole body (legs, arms, and chest), and extension on kicks.
This trick can be seen as the mirror of the Tornado kick. It also forms the basis of all hyperhooks (butterfly twist hyperhook, boxcutter, cheat 720 etc.), and drilling a lot of skip hooks is super important. The hip positioning, leg extension, foot positioning, and spotting all carry over from the skip hook to the harder tricks.
The Back Tuck (more commonly known as the "back flip") is THE most imporant move in tricking - it teaches you how to invert, build air awareness, and is just the coolest looking beginner trick. Some would even say that the back flip is the "gateway" trick; once you learn to backflip, you're hooked on doing flips and tricks forever. The backflip is one of the scariest of the beginner tricks, but is actually not technically the most difficult. All backwards flipping tricks (gainer, corkscrew, full twist) build off of it, it is vital to getting your tricking career started.
The Front Tuck is another fundamental flip - many would find it a lot less scary than the backflip, even if it is technically a bit more complicated (harder to spot your landing). A lot of tricking techniques utilize forward/sideways twisting positions and angles, so learning to set and flip in a front tuck is invaluable.
The Buttefly Kick is a good fundamental to have as it builds into bigger, cooler moves like the Butterfly Twist and the Aerial. But don't count this move out! Coming from Wushu/Kung Fu origins, the Butterfly Kick can look really nice and steezy on it's own. It also is a good move to learn body control and building of momentum throughout the entire body.