Just the imgflip program. You go down to more google fonts for fonts on here you keep on going until you get to the fonts very late in list. Sometimes I use transparent images for the catbrain error ones and some are ones I have to find myself. I just download them and have a folder I keep them in on desktop for use when needed. There's a good bit on here too though. Computer error boxes shouldn't be transparent though sine you write in them. I use a line to cover up words or a white square. Timing the gif can be a challenge at times but not often. I also mix my own shades of colors in the gradient thing for the colors for writing. Tic Tok gifs are more challenging since tic tok is on the side then disappears to bottom corner. Got to time it just right.
It's at bottom of fonts under google free fonts. Shouldn't think you'd get different results in UK but you might. Just switch location to usa on Google if you do.
That is a very comprehensive answer !
I like that you spend so much time on your creations. If a job is worth doing, it's worth doing properly. The cat stream needs people like you. Check your messages 😉
