6 classes are annotated with EntityBrowserWidget in Entity Browser 8

DummyWidget in tests/modules/entity_browser_test/src/Plugin/EntityBrowser/Widget/DummyWidget.php

Dummy widget implementation for test purposes.

EntityForm in modules/entity_form/src/Plugin/EntityBrowser/Widget/EntityForm.php

Provides entity form widget.

MultipleSubmitTestWidget in tests/modules/entity_browser_test/src/Plugin/EntityBrowser/Widget/MultipleSubmitTestWidget.php

Test widget with multiple submit buttons for test purposes.

PagerTestWidget in tests/modules/entity_browser_test/src/Plugin/EntityBrowser/Widget/PagerTestWidget.php

Pager test widget implementation for test purposes.

Upload in src/Plugin/EntityBrowser/Widget/Upload.php

Adds an upload field browser's widget.

View in src/Plugin/EntityBrowser/Widget/View.php

Uses a view to provide entity listing in a browser's widget.