Authoring

Twine

Write interactive narrative fiction (the online version). Create your own adventure game!

OctoStudio

Fabulous Scratch-based authoring system (on mobile) that has better connection to the devices gyroscope, camera, light etc.

Aframep5

A brilliant Javascript p5js library that is integrated with A-Frame so that you can generate A-Frame objects but using the more familiar format of p5js.

WickEditor

Fabulous web-based animation and game-making tool

Leaflet

Nice way to make pages, with images and navigation Nice.

CardStock

Callooh! Callay! A HyperCard clone that doesn't suck AND has programming in Python (rather than HyperTalk). Brilliant!

Alice 3

Amazing 3D tool. You can create scenes and interactions using Scratch-like coding.

Downpour

Fun mobile app (Android, iOS) with which you can make quirky games.

A Frame

A web framework for building virtual reality experiences

Based on Hypercard, this web-based authoring tool looks great. Except the Lil language is, er, not to my taste at all... And you can't (or I can't) just make a stack's size to be fullscreen... and why the hell does the UI fetishize Hypercard, rather than ape it brilliance. I could imagine making wonderful 1bit stuff with this, but it's LOCKED into recreating zombie Hypercard stacks rather than giving them new life. (imo)