What is a pronoun meaning anything at all?

There isn't a single pronoun that perfectly captures the meaning of "anything at all". However, depending on the context, you might use:

* Anything: This is technically a pronoun, but it acts as a noun phrase, referring to any object or concept.

* Whatever: This can be used as a pronoun, referring to something unspecified or unknown. It can also act as a conjunction or adjective.

* Something: This is a pronoun referring to something unspecified or unknown.

Ultimately, the best pronoun to use depends on the specific context of your sentence.

For example:

* "Anything will do, I'm not picky." (Here, "anything" refers to any object or option)

* "I'm open to whatever you want to do." (Here, "whatever" refers to any unspecified activity)

* "I need to buy something for my friend's birthday." (Here, "something" refers to an unspecified gift)

You might also consider using phrases like "no matter what" or "anything and everything" to convey a similar meaning.