Special G/L transactions are non-standard business transactions that are recorded separately from normal transactions. They include bills of exchange, down payments, bank guarantees, and provisions for doubtful debts. Special G/L transactions can be real postings that affect the balance sheet, statistical postings that always use the same offset account, or noted items that serve as reminders but do not impact financial statements. Down payment requests create one-sided memo entries and are considered noted items until a down payment is actually received.