Welcome to the site, nampara17.
I realise there should be 100's of these apps out there but cannot find anything.
Unfortunately, your requirements are what make this not trivial at all and is the reason why there are no apps out there that try to do this. Let me explain. First of all, right-clicking in an application is handled directly
by said application. Without some sort of API or plugin system for a given app, you simply can't hook into all the right-click menus of each and every app. The problem is that the vast majority of apps do not
offer APIs or plugin mechanisms and, even if they did, you'd have to write a separate handler for each application you want to support. This is one of those coding problems that seems easy enough to humans but is terribly difficult to code for. Follow me?
I don't need clipboard controllers and utils, just plain right click, save as... functionality.
It's ironic, but you're almost certainly going to have to use the clipboard for such functionality since it's the only common facility between different applications (when attempting to copy text). You could still accomplish much of what you want by using, say, Ctrl+RightClick to popup a custom menu with a "Save as..." entry. The app would then copy the selected text to clipboard and save it out as a your specified filename. Something like this would actually be trivial to write with a bit of AutoHotkey script. Are you open to this type of workflow?