Chase has 2 business cards under the Ink brand, the Ink Plus and Ink Cash (they used to have an Ink Bold and Ink Classic). The Ink Plus is clearly superior for anyone with significant spending. It gives you a much higher initial bonus and then allows you to do 1 to 1 transfers to certain valuable hotel and airline programs. If your spending is more modest, you may want to convert the card down to an Ink Cash card (or convert anyway if you already have a Sapphire Preferred for personal use).
The Ink Cash and Ink Plus both provide 5X on office supplies (i.e, everything at Staples and Officemax) and Cable/Telecom (e.g., your cable bill, cell phone bill) and both provide 2X on gas. The Ink Plus also provides 2X on hotels and the Ink Cash 2X on restaurants.
Note, this is for businesses, but that includes any type of work where you are comfortable calling yourself a “sole proprietor” and using your social security number for the tax id and your own name for the business name. Anyone that does contract work, sells stuff on ebay, babysits, etc. qualifies as a business.
Also note that there are some reports that you can get more than one of the same Ink card (AND MORE THAN ONE BONUS) if you have more than one business. It is likely that you would need a separate employer identification number for each business, however, one of those can be your own social security number. Applying for an Employer Identification Number (EIN) is not a huge deal, though personally I would not go through the hassle for the sole purpose of a credit card bonus. If you do get an EIN for your 2nd sole proprietorship, make sure to let you accountant know.