With the advent of the 'save group' in the effects stack, I have found myself really using it a lot --THANKS Kdenlive team! What is even better is we can share these grouped effects with each other.
If you look from your home directory ~/.kde/share/apps/kdenlive/effects you will see xml files with the groups names...
Cool HD Film.xml
HOW COOL IS THAT!
It would be cool to set up a github with effects so we could share.
Anyway, this is really great as I used to spend quite a bit of time configuring effects!