Various supplies can be deducted as valid business expenses when they are necessary and directly related to conducting business operations. Some examples of deductible supplies include stationery items (pens, paper), printer ink or toner cartridges, postage expenses (stamps), cleaning supplies used in the workspace (mops, brooms), and even promotional materials like business cards or branded merchandise. It's important to keep accurate records of these expenses to support any deductions claimed during tax filings. Additionally, different jurisdictions may have specific rules regarding deductible business supplies, so it's wise to consult with an accountant or tax professional for guidance relevant to your specific situation.