Aside of your cookie extension, the other 3 could probably have been done with userscripts. I often find a missing feature in a website that I add with userscri

Aside of your cookie extension, the other 3 could probably have been done with userscripts. I often find a missing feature in a website that I add with userscripts. There's also user created userscripts for several websites, like a webcomic reader that preloads pages from several webcomic websites so you don't have to wait on the slow ones.