To make out life a little bit more comfortable and lazy, we could use the Chrome extension.
*Improvement of using Bookmarks works only for Windows in Chrome for now (Mac and Firefox need extra investigation)
To increase the speed of using javascript bookmarklets just install the extension "Speed Dial for Google Chrome" for Chrome
This extension allows you quick access to bookmarklets using keyboard shortcuts. So just place your bookmarklets on the Chrome panel and use Alt+1, Alt+2 ...
Profit👍
P.S. From this article, we found a way to fill web forms by scripts, but what if we do a chain of forms and moreover need to use different scripts/bookmarks. Doing it manually by clicking on the corresponding bookmarks could be also rather long and annoying.