What source are these from?

[Tobikage]

http://kei.iichan.net/m/src/1233447367467.jpg

http://kei.iichan.net/m/src/1233946427688.jpg

http://kei.iichan.net/m/src/1233447678559.jpg

http://kei.iichan.net/m/src/1233447819781.jpg <= This is a real robot correct? Fortress similar to the SDF-1 from Macross?

http://kei.iichan.net/m/src/1234446512583.jpg

[KT Kore]

I don't believe they come from any particular anime. They're either some game art or, more likely, just somebody's art work.

[Vaikyuko]

Probably original artwork, though there's some heavy inspiration from Macross in some. A little Armored Core in one or two of the others.