The Playground in the Lightning component library gone, WebComponents.dev redirecting to LWC.studio, the latter announcing its shutdown at the beginning of 2024 - is there still a place to share and demo LWC code to everyone for free?
The (salesforce.com) recommended place to go today is StackBlitz. The free subscription tier includes unlimited projects and collections, browser-based IDE, ability to edit GitHub repos, 1MB file storage per project, and community support. However, it's not a standard template, so you have to fork from the Salesforce LWC repo. I have personally bookmarked the first link so that I can quickly create a new LWC project whenever I need to.