Not lists that are extra smart, but some smart lists on top of the normal ones I use ;-).

I have things set up in a vaguely GTD kind of way using smart lists i.e. a smart list per project and a smart list per time/place for doing tasks (i.e. context).

Some of my work tasks are listed on an intranet, and I haven't yet got around to automating adding them to RTM, so I have to add them manually. They could be for any of my work projects, so tend to get scattered between my smart lists. As well as the GTD-related tags I add to these tasks, I add an extra tag to say that they've come from this part of the work intranet. I then have an extra smart list that queries for this tag (across work projects), so I have a quick way of checking I've got them all.

If there are work or home tasks I really need to get done before I go away on a trip e.g. check the fridge has nothing that will go off, fill in my work timesheet etc. then I add the tag 'trip' to the relevant task, and then have a smart list that queries for it - a simple way of checking I've done everything before I go.

This flexibility (adding tags and smart lists as I choose) is my favourite thing about GTD - you can set it up however works best for you, rather than having to follow The One True Way that Guru X says you must.