In JS these can be replaced by toolbar.groupsByName, e.g.
$( '.ve-test-toolbar-format' ); // Becomes... ve.init.target.toolbar.groupsByName.format.$element;
In CSS these can be replaced by ve-ui-toolbar-group- but that should be upstreamed to OOUI.
mwgrep "ve-test-toolbar-" arwiki MediaWiki:Common.css arwikiquote MediaWiki:Common.css frwiki MediaWiki:Guidedtour-tour-tuto14.js frwiki MediaWiki:Guidedtour-tour-tuto6.js frwiki MediaWiki:Guidedtour-tour-wikifundi21c.js frwiki MediaWiki:Guidedtour-tour-wikimooc21c.js frwiki MediaWiki:Guidedtour-tour-wikimooc51c.js iswiki MediaWiki:Guidedtour-tour-newpage.js pswiki MediaWiki:Common.css
https://codesearch.wmflabs.org/search/?q=ve-test-toolbar-&i=nope&files=&repos= (no results)