Get All Elements Without An Attribute

<ul>
  <li data-priority>One</li>
  <li data-priority>Two</li>
  <li>Three</li>
  <li data-priority="last">Four</li>
</ul>

First, let us find all elements with "data-priority" attribute present

cy.get('ul li[data-priority]').should('read', [
  'One',
  'Two',
  'Four',
])

We can find all elements without "data-priority" attribute either using jQuery selector :not or Cypress child query command cy.not

// find all elements without "data-priority" attribute present
// using jQuery selector :not
cy.get('ul li:not([data-priority])').should('read', ['Three'])
// find all elements without "data-priority" attribute present
// by first finding all LI elements then using "cy.not" to filter
// the ones with the attribute present
cy.get('ul li').not('[data-priority]').should('read', ['Three'])