I am applying for a standard visitor UK visa. After submitting the application I received a document with the checklist for the documents required. Are all supporting documents listed in checklist required or I can tick just the ones I want to provide?
Unless the checklist you're looking has been personalized to your particular application (which is pretty unlikely), it's there to suggest things you should be sure to think about while putting together your application.
The purpose of the checklist is to help you not missing something because you forgot to include a document you had intended to include, or because it didn't occur to you in the first place that such-and-such document might be helpful for your case. As such, it tends to include something as long as there are some applicants who wouldn't want to forget it. So no, it is not a list of requirements.
It is ultimately up to you as an applicant to submit documentation that is convincing and makes sense for supporting your application.
It is completely expected that the way you will handle some checklist items is to think, "hmmm ... no, it wouldn't make sense for someone in my situation to include that", and move on to the next item. Then the checklist has served its purpose!