SFP+ 10Gbase-T 3rd party optics started hitting the market this year, but none of the major switch vendors offer them yet, so the coding effectively lies about what cable type it is. Just an option to keep in your back pocket, as onboard 10Gb is typically 10Gbase-T. Thankfully, onboard SFP+ is becoming more common however.
For short distances of known length, twinax cables which are technically copper can be used. They're thinner than regular cat6a but only about the same as thin 6a and thicker than typical unshielded Duplex fiber patch cables. Twinax can be handy if connecting Arista switches to anything else that restricts 3rd party optics, as Arista only restricts other cable types. Twinax is also the cheapest option.
For short distances of known length, twinax cables which are technically copper can be used. They're thinner than regular cat6a but only about the same as thin 6a and thicker than typical unshielded Duplex fiber patch cables. Twinax can be handy if connecting Arista switches to anything else that restricts 3rd party optics, as Arista only restricts other cable types. Twinax is also the cheapest option.