As @bonjour_17 advised, the fewer plugins, the better. To have a list of Things with checked checkboxes to save, store them in a custom state (type = API call response type).

If your toggle switch/checkbox (which appears to be a custom one) allows you to trigger the workflow through which you can add/remove the current cell Thing from the custom state, then you have everything needed to create such a list of Things that can be saved.

If your checkbox doesn’t allow this, then you can:

  1. Add an input (1px x 1px) to the RG cell
  2. Add the condition “when checkbox checked, initial content is 1; if not, 0” to it
  3. Add two workflows to the page type Elements > An input value changed:
  • One should fire when the custom state contains the current cell Thing and remove it from the custom state
  • The second should fire when the custom state doesn’t contain the current cell Thing and add it to the custom state

Then you can save this custom state list of Things into the DB.