Bank statements. One sort of financial record is a bank statement. Your bank will regularly send a statement containing information showing income (credits) and outgoings (debits) on your bank account.
They're synonyms. Gain is the most general. Attain usually means to reach a goal or milestone (he attained the rank of captain). Obtain usually implies careful planning or some effort to get to the thing or goal. But they have probably something like 80% overlap in meaning.
The difference between a hoard and a collection is how these items are organised. A collection is usually well-ordered and the items are easily accessible. A hoard is usually very disorganised, takes up a lot of room and the items are largely inaccessible.