In IELTS Writing and other academic writings, we know that they require some rules to avoid being informal. Certainly, there is a list of words that should not be first in a sentence. Ultimately, any word could start a sentence, depending on how formal or informal the writing is, the context used, etc.
In formal writing, it is generally frowned upon to start a sentence with a coordinating conjunction.
In list form.
And (sometimes I used this conjunction in IELTS and my teacher said using "and" or "but" is fine, but he told me should remember this for the after-IELTS, i.e. university assignment)
My tip to remember this list is the acronym FANBOYS.
As a note, in an informal writing such as free writing, poetry, etc we are not bound by the compulsory same rules. Whilst some may not be grammatically correct, it might make the most sense to break the rules, perhaps to keep a character in character, or to maintain a specific tone. Therefore in informal writing, it is up to your decision when some certain rules need to be followed or broken. Therefore, it's safe to assume that FANBOYS should be avoided when starting a sentence just to be on the safe side.
Do yall have other ideas ? Feel free to share your opinions