You can do that with any theme by editing the css for your links.
Do you have a site? Are you using a theme that you would like to add that functionality to?
If you need to search for a plugin you can try here: https://wordpress.org/plugins/
Thanks for the quick reply, but that’s a pretty general answer. I particularly like the way the buttons change shape in the mobile view. I need to overlay these buttons on a background image, maybe a slider. I have done a lot of searching but haven’t found this yet. The theme I use most often is Avada.
Well you asked a pretty general question. What you have asked for can be done very easily with a few lines of HTML and CSS in any theme. Something like that is not theme or plugin material. It is just a button style that can be done very easily. If you use your browser’s developer tools and view the code you could probably copy and paste it right into your theme.
If you provide a link to a page you would like this effect on I am sure someone would be able to assist you in creating that effect. Just make sure you ask in the appropriate theme forum.