Does Vivaldi have add block plugins ??
When you type in "about:plugins" you get no indication that Vivaldi has it's own ad blocker. This has been requested of Vivaldi to have their own integrated ad blocker, and I too would love it if they get it eventually. I'm sure they will get it at some point.
And I see this is your first post. Welcome to the forum! Are you new to using Vivaldi? It's a pretty awesome browser, isn't it?
There is a per-page content blocker under "page actions" down to the right on the status bar. It is not a plugin or extension, but built in to the browser. I expect that over time this will be refined and enhanced, so that it can be made to function like an ad-blocker, and can be persistently enabled, rather than only on a per-page basis.