None but Allah can help us. Here, "None" is-

• None but Allah can help us.- Here, "None" is an Indefinite pronoun.​• ​Indefinite Pronoun:- অনির্দিষ্ট ব্যক্তি বা বস্তু কে বোঝাতে যে Pronoun ব্যবহৃত হয় সে pronoun কে বলে Indefinite Pronoun.- Indefinite pronoun এর কয়েকটি উদাহরণ হল: All, one, none, anyone, some ইত্যাদি।​​• Types of Pronouns:1. Personal Pronoun: I, you, they, he, she, etc.2. Interrogative Pronoun: Who, What, which, etc.3. Distributive Pronoun: Each, either, neither, etc.4. Demonstrative Pronoun: This, such, that, etc.5. Relative Pronoun: Who, what, which, that, etc.6. Reciprocal Pronoun: Each other, one another, etc.7. Reflexive Pronoun: Myself, yourself, herself, etc.8. Indefinite Pronoun: One, any, some, etc.Source: A Passage to the English Language by S. M. Zakir Hussain.