If you want some awesome concept art and game stuff I would recommend tumblr. Tumblrs are great for game stuff actually. I personally follow some of my favorite indie bands on Instagram because they always post interesting pictures from their travels. Here are some blogs/tumblrs: http://exquisitebeast.tumblr.com/…
Yeah there isn't much concept-art type stuff on instagram that i know of. I kind of follow people on instagram for purely entertainment purposes. Like this guy who has been making news lately - A extremely wealthy teenager (inherited) showing off his ridiculous lifestyle while dissing us everyday folks (peasants…