If you watch the top players you'll notice that most have only one or two basic serving motions that they use over and over. The majority just do forehand pendulum and reverse pendulum serves. This allows them to do every possible type of spin, including sidespin both ways. Most have a few "trick" serves they'll pull out sometimes, but the large majority of their serves are almost relentlessly the same few motions, though the spins vary quite a bit.
But they are world-class players playing other world-class players, who are not particularly vulnerable to trick serves or varying service motions. That's not true of the large majority of players. Against them, you should also have only one or two basic serving motions that you use most of the time. But you will have a huge advantage if you can regularly pull out other serving motions, as long as you can do them effectively.
After a game or so, most players adjust to an opponent's serving motion. But what if you are able to pull out other ones, and keep them guessing? For example, after a few forehand pendulum (or regular or reverse), throw in a backhand serve, or tomahawk serve, or any of a zillion other possibilities. They key is not just throw out these serves as just "trick" serves, but actually learn to do them well. Otherwise they are one-serve wonders, which have value if used perhaps one time, but not much beyond that. Instead, develop these other serves so you can pull them perhaps out a few times each game, and perhaps get a few "easy" points.
It takes a lot of practice to develop multiple serving motions, and just as much time getting comfortable using them in games (where you not only can do the serves, but get used to the various returns). It's a lot of work for a seemingly small return. But is it really a small return? Players spend years improving parts of their games only marginally. Perfect a new serving motion, and you may find opponents struggling against your serves later and later into games, including those all-important points near the end of a close game.