UI Widget & Component Toolkits
On Web Platform: 1
- Bootstrap 3 or Bootstrap 4
- Kendo UI for jQuery [free to $]
- Office UI Fabric
- Semantic UI
- Webix [$]
React Specific, On Web Platform: 2
Native Desktop/Laptop/Netbook Apps via Web Platform (i.e. used with NW.js and Electron):
Mobile/Tablet Specific On Web Platform (i.e. used with touch focused UI's):
1 If you need a basic set of UI Widgets/Components start with Semantic UI. If you are building something that needs a grid, spreadsheet, or pivot grid you'll have to look at Kendo UI or Webix. Also, keep in mind that most of these solutions still require jQuery.
2 If I was going to build a React app and needed a toolkit of widgets/components off the shelf I'd with Semantic-UI-React and/or Ant Design, or I would accept that fact the some of the components I want to take off the shelf and use have a hard dependency on jQuery.