Well considering all the decades have one or two great anime you have listed aswell as the others that were released in those specific Times it's going to be very hard.
Well I'm sorry to be choosing 3 decades but in my opinion they all have significant Anime .
So my favourites would 70s 80s 90s 2000. Well my favourites from all these decades would be NGE 90s, FMA Present, GITS series 90s- ???, Mobile suit gundam 70s, Studio ghibli films Present and Akira 80s.
Obviously I have many more. But these stand out in the particular Decades I have picked out.