I typically do everything custom these days. In the past I would use Bootstrap, Semantic or one of the many other CSS frameworks but I found that I add a lot of size to my applications when I only used a few things from it. Most features (sidebars, grids, menus...) are simple enough to just implement on your own. I was a graphic designer that moved into development so I feel I have a pretty good sense of design and UX.

I do however use various charting libraries out there for ReactJS as they are typically quite well done and small in size. If I need something a little more custom I'll install D3 and build it out.

For backend I have used Node/Express quite a bit to serve API's and such. But as mentioned in my previous post lately I've been using system programming languages a lot more for building backend things mostly as a learning exercise and because I have the freedom to do that in my job.

Building out these tools and seeing them being used daily from nearly all employees in a ~400 person company is really rewarding. It really gives me a sense of appreciation for the work I do and I get a lot of good suggestions on how to improve the applications that in turn improve the work these employees do.

Other things I've used in the past for various projects include Ionic Framework & PhoneGap (mobile app), Zephyr RTOS (BLE Mesh Programming), React Native, Angular, Electron (Visitor Check In/Out Kiosks), and lots of CSS frameworks (too many to name).

React SemanticUI is great.