I can't believe I haven't done this before, but from now on I will share my favorite pieces at the release of every new Magic: the Gathering set. I tried to limit it to one per artist, though most artists on this list had multiple pieces worthy of note. That being said, a top 10 is a very narrow affair, and you should check out the work of Peter Mohrbacher, Jaime Jones, Jason Chan, Karl Kopinski, and many others who worked on this set. Any omissions are for the sake of brevity.
These are the artists and the quality of work I aspire to, and this list serves as a marker of how far I have to go. It is also a reminder of why I love what I do, and will never stop striving to get better.
Welcome to Theros:
10. Defend the Hearth by Raymond Swanland
9. Phalanx Leader & Ordeal of Nylea by Dave Palumbo
8. Erebos, God of the Dead by Peter Mohrbacher
7. Abhorrent Overlord & Fleecemane Lion by Slawomir Maniak
6. Hopeful Eidolon by Min Yum
5. Voyaging Satyr & Elspeth by Tyler Jacobson
4. Prognotic Sphinx by Steve Prescott
3. Destructive Revelry by Kev Walker
2. Hythonia the Cruel & Nylea, God of the Hunt by Chris Rahn
1. Ashiok, Nightmare Weaver by Karla Ortiz