"How Many Keleseths" is too many? Let's find out!
This is probably the dumbest and most fun deck I've ever made. I doubt this is competitively viable to any degree, I've only been playing it in casual mode. The idea is to drop Keleseth and shuffle as many back in the deck as you can via Spirit of the Dead. Your draw engines are a'plenty: Northshire, Witchwood Piper, and Bwomsamdi. Unidentified Elixir because pretty much all of the options are decent (especially Lifesteal) and sometimes you highroll and get the "+2/+2 and Deathrattle: Return this to your hand" on Keleseth.
Benedictus both for the meme factor and you're usually far closer to fatigue than your opponent.
If you get lucky you can drop both Spirit of the Deads with Keleseth. When it shuffles two back and you draw it - Keleseth is active because they're now 1-cost, not 2-cost.
1/8/19 edit: I've tested out cutting Clerics and 1x Spirit of the Dead to guarantee that Witchwood Piper draws Keleseth, but the draw power of Cleric is just too good, and having double Spirit of the Dead gives you more flexibility of when you play them.
2/14/19 edit: Took out Lyra and Benedictus for Omega Medic. I don't think you really need Lyra, and Benedictus usually screws up your future Keleseth buffs. Omega Medic on 10 can help you survive against midrange Hunters.
3/22/19: took out the unidentified elixirs for zola and brewmaster because they do the same thing without the rng.