Scion of the Ur-Dragon offers an easy, repeatable way for you to search out dragons from your deck and put them into your graveyard, which is already a good enough ability on its own for fueling your reanimator cards
Saheelis dynamic genius is truly unlimited in its potential and now you can prove it to your friends on the racetrack OR battlefield
But that poorly received push against Urza has her hitting outside of the Top Five
Plus, Geier Reach Sanitarium gives us another way to get card types in the graveyard to turn on our Manic Scribe
It makes creatures, although its expensive, and it can transform into a powerful beater that can end games for a relatively paltry cost
For seven mana you get an on curve 7/7 with four powerful keywords - flying (evasion), vigilance (very strong in multiplayer swinging at people in the air for Commander Damage and then holding the fort), deathtouch (no one wants to block) lifelink (nice double life swing for that 7 damage.)