Places to get images, sounds and more…
Sites that have royalty-free and Creative Commons images, sounds, 3D models and data collections for you go grab, modify and use. Note: Make sure you understand Creative Commons licenses, especially if creating a commercial product.
Thunkable is based on a very similar free tool call MIT App Inventor. Because lots of people create Extensions for it, that also work with Thunkable, you can find extra code, called Extensions which do everything from rotation detection, to sound analysis, to QR code recognition and connecting to other devices.
Large collection of stacks for you to
The Noun Project has millions of images available as both .png and .svg files (which you can edit). Maybe one of these might be the start of your logo or design.
* Remember to credit the original author.
YouTube has bots that check your videos to make sure you haven't used a copyrighted music track in your video. All these tracks are free to use on YouTube, Facebook, Instagram & Twitch without copyright issues.
This guide shows you how to download tracks from the Audio Library.
There are also lots of sound effects to download too.
Pay special attention to attribution requirements, with any audio user ever.
The City of York Council provides lots of data about all sorts of things in your area, such as spending or footfall numbers in the town in .csv format.
There are even .kml files of listed trees, or where litter bins are, that can be imported into Google My Maps or Google Earth.
Choosing a text editor for coding is a very personal choice. Some have "too many" features, others are too simple. You may need to try more than a few to find one that you like working in, but it's not until you start on an actual project, that you'll be really able to tell.