John B. Kalla

Freeware, but ultra basic (but a lot of ppl just need this) : Microsoft Gif Animator.
 
Open source, but I recommended first MS gif Animator just because this one I haven't tested, but OS software gets always my preferent vote, is this little thing, a bit more advanced than MS gif animator, called GifApp.
 
Gale is amazing, much focused in pixel art painted sprites (in case you do that thing). And free. For actually loading and saving animated gifs, is needed the commercial version, that price in yens I believe is around 18$, and I think you can purchase directly there even if you are not in Japan (used to be an issue with japanese software, the payment platforms had its issues. I think you can purchase it right away there.)
 
The one used in mobile game studios like Gameloft (so that's quite remarkable) is in a good portion of projects, (or used to be, am now a bit disconnected, not working in that anymore) is Pro motion. i don't particularly like it, but some colleague insists is the best piece on earth to make sprites.(my main tool at jobs was always just PS combined with Animation Shop from an old PSP 7.x/8.x, loading layered PSDs to preview the anim and draw at real time animation). There's a free version very limited, but i don't know your needs. It does export animated gifs, again, dunno if does so the free one.
 
Going higher in features(or actually, equal or less than Pro motion, but this one heading higher resolution work more than pure pixel art) and capabilities, (but for pixel art probably Gale and Pro Motion are better) , DragonBones. Dunno if can export gif anim (you can always just load the PNGs of the anims into MS gif animator.). Seems is free, I yet don't understand why...price 60$ or so, I believe...
 
My favorite for sprites (of higher resolution; Casual/shareware/web/tablet/phone games, not so much pixel art) animation : Spine. used largely by many Unity engine game studios. Funnily, I've never seen if it exports gif animated, but I'd bet that thing does even make your morning coffee, so, yep. But yes, expensive... You check the features and the good name among pros that it has, and you then you understand the why...
 
Edit: Of course, you can use my favorite free painting tool (which I plan to use in perfect combination with AD and A. Photo) Krita which in version 3.x stable adds animation. A bit over complex UI though for newcomers, for what is the animation module. (opposite to its painting UI) , but I like how advanced it is already, will have a look with more time at some other moment.
 
And at last, there are sites to make your gif anims, and download them, but I never like that for privacy reason, and lack of control.

I've just made an animated GIF to explain a comment in this forum and I realised how simple it is to do in PhotoShop. Unfortunately... I had to go to PhotoShop to do it.
 
I know animated GIFs probably fall into the animation category, but it would be great to able to export layers as frames in the same way Illustrator does when it exports an animated SVG. No massive feature set, just a few simple settings at export stage.

Hi @Sagi,
Welcome to the forums. 
Affinity does not require an internet connection for activation. You would only need the email address and the product key to activate it. 
Thanks,
Gabe.