HackerWeb - A simple and readable Hacker News app
Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
HackerScroll - Read top articles from HackerNews in a clean, simple and minimal interface without ads or any other distractions.
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.
HNwatcher - Track keywords and users on Hacker News
Bubble.io - Building tech is slow and expensive. Bubble is the most powerful no-code platform for creating digital products.