Seconding/thirding KDEnlive and Krita and OBS!
There's a freeware version of Komodo Edit (or maybe it's called Komodo IDE, the one I use is called Komodo Edit) for the types that like coding, which I'm only bringing up in case the design stuff includes web/interface design.
In my personal experience I've found GIMP better for photo editing (it can be done in Krita as well) so would recommend that for photos.
And I haven't used Inkscape much but that's pretty good for vectoring and svg.
Are you including Thunderbird with your Firefox coverage?