Which of the accounts are decreased on the debit side and increased on the credit side?

In the income statement, the income accounts. In the balance sheet, the liabilities and equity.

Explanation:

These accounts are opposite to expenses, in the case of the income statement; and to assets, in the case of balance sheet. When an income is registered, a credit increases this account, and as a counterpart, a debit increases assets (if a sales were made in cash).