The best alternatives to Curius are Tabs Folders, Curabase, and LinkBin. If these 3 options don't work for you, we've listed a few more alternatives below.
Curabase makes it easy for teams or individuals to share bookmarks. We have a simple web application where you curate links into groups, and groups into pages. Share them publicly or privately. Free to try, no email or signup required.
LinkBin is an app for iOS, iPadOS and macOS that allows temporary storage of links. Saving links is dead simple and you can automate everything with Apple's Shortcuts app.
Stash is an extension that lets you save your favorite links to your phone directly from any app, in a list only you can see. Keep track of pictures, videos, links you find or items you want.
Flub (for Fan Club) is a web application that allows you to offer your visitors a single page to list all your links (social networks, community links). It's free, fast, and intuitive!
Midinote try to solve this question: how do I take notes when I still don't know which category it belongs to, also, midinote lets you can visualize your notes in a mindmap-like view, and browse your knowledge in a Wikipedia-like approach.
LinkVault is an app that helps you to save links from different apps in a centralized place so that you don't have to maintain part of your collections on multiple apps. It also provides functionality to tag and search links easily.