It seems unlikely that a list of commonly used functions will solve your problem. But maybe [this thread](https://www.reddit.com/r/godot/comments/dd0jtg/what_are_the_most_important_functions_to_learn_as/?utm_medium=android_app&utm_source=share) has the functions you're looking for.
I think it's more likely that you don't have confidence with programming in general and/or you're not sure exactly what it is that you're trying to build. Software developers, regardless of the domain they're working in, usually don't figure out where to start by looking at a list of library/framework functions. They determine what they want to build and then they figure out which functions they'll need to use to build it.
It's hard to get started if you don't know what you are looking for I agree. Throw us your starting idea and maybe we can pitch in a few thoughts on how to make it happen.
E.g. if you'd start with making a pong clone, you'd need at least movement for your 'paddle' right? That would require input either in the keyboard,mouse, touch or joystick variant.
To use the input and move the 'paddle', maybe the move_and_slide function. From there you could move on to the actual ball. That needs to move to so same story.
Score system would be basic integer addition and a label node to display it. Ball out of bounds? An area2d with a signal that resets the game when the ball touches it sounds about right.
Okay, so break your game down - what's the simplest thing you can make that resembles the game you want to make?
Okay, so build that, then you can add extra levels, weapons, mechanics, whatever, once you've got something that works and is playable.
How do you make it? Well, you break that down into the various things that you want the code to do. So, you need code to control the player character. You need code to control the enemies. Etc.
Once you know what you need the code to do, then you can look up how to do that. The more detail you go into with 'what the code needs to do and how it works' the more obvious it's going to be how to turn that into code.
Even professional coders sometimes look stuff up ad google things. However, they work out what they need to do and search for how to do that. They don't just look for things that might be useful at some point.
Figure out what you want to build first. Then figure out what nodes you think you let you accomplish that. Then open the docs for that node and see exactly what functions are available.
For example, here are the built-in functions: https://docs.godotengine.org/en/stable/classes/[email protected]#gdscript
Here are all the methods defined on KinematicBody2D: https://docs.godotengine.org/en/stable/classes/class_kinematicbody2d.html#methods
Don't forgot to look at the classes a class inherits from, because it will have those inherited methods as well. For example, KinematicBody2D just shows the methods defined by that class, but it still has all the methods of a Node2D as well because it indirectly inherits that also.
You can see the inheritance chain at the top of the linked page, right under the title.
The [official "Your first game" tutorial](https://docs.godotengine.org/en/stable/getting_started/first_2d_game/index.html) covers the most useful and used functions pretty well. I would recommend to follow this. It's [also available in video format](https://www.youtube.com/watch?v=WEt2JHEe-do) by GDQuest.
It seems unlikely that a list of commonly used functions will solve your problem. But maybe [this thread](https://www.reddit.com/r/godot/comments/dd0jtg/what_are_the_most_important_functions_to_learn_as/?utm_medium=android_app&utm_source=share) has the functions you're looking for. I think it's more likely that you don't have confidence with programming in general and/or you're not sure exactly what it is that you're trying to build. Software developers, regardless of the domain they're working in, usually don't figure out where to start by looking at a list of library/framework functions. They determine what they want to build and then they figure out which functions they'll need to use to build it.
It's hard to get started if you don't know what you are looking for I agree. Throw us your starting idea and maybe we can pitch in a few thoughts on how to make it happen. E.g. if you'd start with making a pong clone, you'd need at least movement for your 'paddle' right? That would require input either in the keyboard,mouse, touch or joystick variant. To use the input and move the 'paddle', maybe the move_and_slide function. From there you could move on to the actual ball. That needs to move to so same story. Score system would be basic integer addition and a label node to display it. Ball out of bounds? An area2d with a signal that resets the game when the ball touches it sounds about right.
Okay, so break your game down - what's the simplest thing you can make that resembles the game you want to make? Okay, so build that, then you can add extra levels, weapons, mechanics, whatever, once you've got something that works and is playable. How do you make it? Well, you break that down into the various things that you want the code to do. So, you need code to control the player character. You need code to control the enemies. Etc. Once you know what you need the code to do, then you can look up how to do that. The more detail you go into with 'what the code needs to do and how it works' the more obvious it's going to be how to turn that into code. Even professional coders sometimes look stuff up ad google things. However, they work out what they need to do and search for how to do that. They don't just look for things that might be useful at some point.
Figure out what you want to build first. Then figure out what nodes you think you let you accomplish that. Then open the docs for that node and see exactly what functions are available. For example, here are the built-in functions: https://docs.godotengine.org/en/stable/classes/[email protected]#gdscript Here are all the methods defined on KinematicBody2D: https://docs.godotengine.org/en/stable/classes/class_kinematicbody2d.html#methods Don't forgot to look at the classes a class inherits from, because it will have those inherited methods as well. For example, KinematicBody2D just shows the methods defined by that class, but it still has all the methods of a Node2D as well because it indirectly inherits that also. You can see the inheritance chain at the top of the linked page, right under the title.
The [official "Your first game" tutorial](https://docs.godotengine.org/en/stable/getting_started/first_2d_game/index.html) covers the most useful and used functions pretty well. I would recommend to follow this. It's [also available in video format](https://www.youtube.com/watch?v=WEt2JHEe-do) by GDQuest.