Exsanguinate is a pretty useful card for any deck that plays black and has a use for gaining extra life.
I don't know if you have quite enough life gain to make it more than situational, but I think Cradle of Vitality could be very interesting under the right circumstances. Similarly for Unspeakable Symbol , going in the other direction.
My group of friends have outright banned all infinite combos aswe try to have fun in this format. Thank you anyways
It's not an "infinite combo" per say, but a great interaction is Karmic Guide , Reveillark , Puppeteer Clique , Mikaeus, the Unhallowed , and Vish Kal, Blood Arbiter in any combination of your graveyard and/or battlefield, it's endless instant-speed graveyard recursion and continuous board wipe. Also makes Vish kal huge. Plus those are just great cards for this deck in general.
Sorry for the many posts, but even though I haven't seen this card played in any edh deck, Helm of Possession seems freaking amazing in a sac dec where infinite combos are banned :-). I made a casual deck for my brother and it's an all-star :-)