Daydream Shimmer is amazing.
http://drsunnybun.deviantart.com/art/Sunset-Shimmer-564106529
Hope it gets colored by someone.
http://twilite-sparkleplz.deviantart.com/art/S-sketch-555903449
At least until a decent Science Sunset pic comes along.
http://billerakdragondorado.deviantart.com/art/How-s-my-new-look-550351321
The majority of the Sunset Shimmer avatars that I've used are by the amazingly talented twilite-sparkleplz. She draws the best Sunset Shimmer I've seen in this fandom (and even has a cool backstory for her, which just makes it all the better).
This is the first one that started things off:
Seriously, it's almost three years to the day since I've last made a blog post on my profile. Crazy, right? I didn't even ever do anything with that short story thing (If you wanna bother looking at it with the proper font settings and everything intact, it's over here on my Google Drive).