GM Screen
A kind of drawer on the bottom of the screen with a grid you can freely fill with sheets, tables, whatever you need. Great help for navigation. You can also have several "pages" and make some available to your players.

Simple Calender & Small time
Also a very handy tool to track your time & take notes of when a critical injury is healed etc. If you're into it, it can automatically adjust the brightness depending on the time of day. If I recall correctly, you first activate the calender and import the official modules after that, the calender will be automatically set up for you. But someone should elaborate on this further / give me time to research / research-try it themselves.

combat carousel + initiative quickchange
a helpful widget to visualise who's turn it is. Initiative is rolled instead of drawn, which I'm not a big fan of anyways.

Quick insert search widget
press ctrl-space and search for everything, in all lists (items, enziclopedia, scenes, actors...) at once. great for starting out until you know your way around.

world explorer
players only need to make a roll for lead the way when they haven't been to the hex before. they also only get xp once per hex. The world explorer helps you with that by overlaying another picture which you can remove hex by hex. Configuration is done in the scene config, together with grid, lighting etc. I use a black and white map of the ravenlands together with visibility. Once I find the original author I will reupload it and share the link here.

Popout
I personally don't use it because I have a big screen and prefer to zoom out a bit more (use the address bar of your browser, ctrl +/- won't do it), but I have it installed for my players. There used to be issues with functionality of popped-out elements, but I'm not up to date about the state of things in this regard.

That's a really good question and potentially a tremendous help for many. Thank you for bringing it up.

Dice so nice!
I believe this is a no-brainer to add. What some might not know is you can add animations to individual results: Go to "configure settings", find the secion for dice-so-nice and go ti the 3D settings. "Special Effects" (in the top row) lets you add special effects. I have "blaze" on the 6s of db (base) ,ds (skill) ,dg (gear) and "glass impact" on 1s of db & dg.

year Zero actions / year zero Combat
I have only now discovered those, I believe, though, they could supersede combat carousel & initiative quick change.