Will there be a theme for the jam? Personally, I would like to have one, it makes it easier to start a game. Otherwise there are too many possibilities.

I don't thing there's a set theme, but we could group up and have similar theme.

The theme is "learn about Godot Engine"

This game jam is meant for beginners I guess, so a theme is not nessessary.

Eh, I don't think we need a theme. If people really want one, the theme can be "keep it simple" :D

If you need motivation for something simple, a great resource (even for serious projects) are old game manuals, some of these look like design documents.

A great site for this kind of resources is https://www.atariage.com

For example take a look at this page of the manual of Human Cannonball

Open a book at a random page, pick a random word or phrase - there's your theme.  Or repeat until you have a few that spark off each other.

If anyone wants to quickly generate a game idea, I've created this little tool:
https://gameideagenerator.online/