Fevered Visions A Howling Mine effect and a payoff in one, this staple of Shadows over Innistrad Limited seems good in the context of this list
Atraxa, Praetors Voice Arguably the best strategy for an Infect-based Commander deck is to play it around a completely different mechanic: Proliferate
Special thanks to cryogen at MTGNexus for his continued maintenance of the Commander Quarterly Update archive, which I referenced in writing this piece
There is a danger to the 40-card deck: running out of win conditions
The duels and tournament play allowed you to play with any deck you built, or the pre-made decks that came with the game, against any one opponent, or you could run the gauntlet and play a tournament
Since its indestructibility comes in counter form, you can use proliferate so you can activate its second ability and keep it safe