Can a "for profit" LLC accept financial gifts?

You may accept them, but you'd have to pay taxes on them (or  technically, the LLC has to pay, though if you have pass through tax treatment, that's the same as you paying). To oversimplify slightly, any money received by an LLC which is not repayment of a loan or a valid business expense borne by the LLC for a business purpose is income, no matter what you call it; it has to be properly reported and taxes paid on it.

Note that  if the LLC does not properly disclose its status, what it does with the money, that it's not a tax-exempt entity, etc., it potentially could get in trouble (fraud, etc.) for soliciting or accepting "gifts" if the givers have a misapprehension about the entity. I am not sure why a for profit entity would receive financial "gifts"--I have not heard of this. You should be careful about this, since anything unusual is prone to misunderstanding and misunderstandings could give rise to liability.