The sentence "She is one of those rare individuals who goes out of her way to help others" contains an error in subject-verb agreement. The phrase "who goes out of her way" is incorrect because "who" refers to "those rare individuals," which is plural. Therefore, the verb must also be plural. The correct phrase should be "who go out of their way" to maintain agreement in number. Here's the corrected sentence:
She is one of those rare individuals who go out of their way to help others.