List of Games that can only be bought in certain Steam Region Stores that are ROW

updated as unclear

Your title mentions Region Locked games... but your Post says "can be gifted and activated in UK" which is the opposite to Region Locked.
From what I know everything coming out of a Canadian Steam Store is ROW.

You can trade with Japan, Canada, Usa, EU1 and EU2 too

You mean games sold only on US Region, or locked games?

Duck Dynasty can't be activated at all in certain regions. I'll need to hunt down a Ps3 copy to play it. :P

Dawn of Discovery = Anno 1404 in EU/UK

Couple of other games have different names too.
(Mensa, Battle vs Chess)

Well yes. stuff that I can't see in the UK Store that can be purchased from other ROW Regions, sorry if that is unclear, i have reworded it

Can you see Dragon Age Origins: Ultimate Edition from the UK?

Can only buy DAO and Awakening from my region, so I got my copy from a US trader.

Saw can only be bought in brazil if i remember correctly

I'm not sure I get you, but would games such as Urban Chaos count? I can't see it in the french store despite it being row (think it's a translation issue).