@Natehenry As Samantha correctly asked, if you want specific information, you should provide your camera model.
You ask: "Which ones are necessary or most used?"
It very much depends on what subjects you are going to shoot. If you shoot portraits or relatively still subjects, one uses still to single shot or low speed modes. For moving objects, one can go to H or H+, depending upon the speed of the subjects' movements. For example, a sports game like ice hockey, sprinter, or bird in flight might suit H+. Remember that the faster the shooting rate the faster your cards have to be to clear the buffer, or you will get the camera freezing while it does so, which can be annoying.
The shooting mode will be significantly impacted by your shutter mode - mechanical, 1st Curtain mechanical but otherwise electronic, or fully electronic. The speed of shooting increases with each. The Canon EOS R6MkII can achieve 40 f/sec, and the R7 30 f/sec, however high speed electronic has impacts with sensor lag, where vertical objects become slanted or things like rotor blades become highly curved as the delay in the sensor refreshing the image as it moves down from top to bottom will record fast-moving objects in different positions.
It's all in your manual. For example, here is a screen dump from the Manual for the EOS R6.
For camera capable of Dual Pixel RAW shooting there is also this table from the EOS R5
