If you need more spots beyond your Thunder, or in a format that is Highlandered, this is great
1 Raphael, Fiendish Savior
While "spell" does include creatures, artifacts, and enchantments in the context of Rolling Attack, the inclusion of Electric Thunder really promotes buffing him up with spells like Titan's Strength, Brute Force, Samut's Sprint, and Infuriate to keep the damage going to every character possible
Its relatively cheap, it provides repeatable self-mill on attack triggers, and it helps to pay off other graveyard synergies by creating creature tokens
The leaker does caveat this with the fact that they datamined this information and its subject to change, but it seems unlikely that the date will shift wildly