Block Flash from loading automatically and allow content only on selected sites.
Flashcontrol is a plugin blocking extension that blocks Flash and replaces its content with a placeholder. Unblock desired content by clicking placeholders, selecting the toolbar menu, or by configuring Flashcontrol's filter settings.
Included are several tools to help you manage a list of allowed sites, such as a dashboard for your filters and a DevTools panel that logs Flash URLs.
In general, Flashcontrol helps lower the amount of memory and CPU used by Flash which would otherwise slow down websites.
Some websites use HTML5 instead of Flash for audio/video. If you want to block HTML5, try the extension "Disable HTML5 Autoplay" https://chrome.google.com/webstore/detail/disable-html5-autoplay/efdhoaajjjgckpbkoglidkeendpkolai/