Salesforce has introduced an online editor to try out Lightning Web Components. Lightning Web Components is the new UI development approach that Salesforce has; this is an evolution from the current Aura framework. Salesforce is to allow both Lightning Web Components and Aura frameworks to exist side-by-side.
To not just experiment, but also evaluate design considerations playground can be used. By using the instructions here, new Lightning Web Components can also be created on the interactive code Playground editor.
Dual Listbox is a control that that just shows a bunch of values on the left-side and allows user to choose the values and move them to right-side.
Can dual listbox handle thousands of values on the left-side? Playground makes it quite easy to change the values of the values loaded.