Pubg war? Let me explain...
The idea behind these grids is that you are supposed to use groups that people with a normal level of general knowledge have heard of.

Well I got full marks with a normal level of general knowledge. You dont need to know every single square to make the connections.

@Nighteyes
PubG is quite a famous Battle Royale I would say. I agree it's probably not the most obvious available answer, but I think it's perfectly reasonable to expect a fair number of people to recognise it as a battle-based video game.
Your comment seems a tad condescending tbh - I thought the grid was a lot of fun

The idea behind these grids is to give your brain a work out and to learn a new thing like PubG is great every day a school day!