Vivaldi gives you the option to assign a nickname to a Web page, which you can then use to quickly load that page, by typing the nickname in the address bar.
Go to the Speed Dial page and click on Bookmarks in the top menu.
Click any bookmark and add a Nickname to the right side panel.
Go to the address bar and type a saved Nickname and after that press Enter. You will also see the assigned webpage in a drop-down list.