Morgue Toad ? shrug

Syphon Flesh would be great.

Have you considered using Eldrazi Spawn token generators? You would be ramping your mana up while fueling Thraximundar with counters. I'm thinking you should try at least Rapacious One and Pawn of Ulamog would be a nice fit.

So, What would be a good idea to remove for said cards?

Urabrask the Hidden seems a bit out-of-place to me. Haste is cool, but your Commander a good chunk of creatures in here already have it.

As for what else, I couldn't tell you. The list seems to have a lot of synergy as it is.

I agree, Syphon Flesh would be good. I have that in my build.

Grixis Panorama can't be used to fetch dual lands. I would remove it and put Terramorphic Expanse or Evolving Wilds because you need another land in play to trigger it's ability.

Grixis Panorama can't be used to fetch dual-lands. It says "Search your library for a basic Island, Swamp, or Mountain..."

Hmmm, I obviously misread the card. Thanks for pointing that out lol. So, I'll probably...

-Grixis Panorama

+Evolving Wilds

-Urabrask the Hidden

+Rapacious One

Grixis Panorama isn't that bad, though, and it's arguably better than Evolving Wilds . It taps for colorless mana the turn you drop it. It might require an activation cost to use, but it really won't stop you from hitting your land-drops.

There are pros and cons to both, really.

Bloodstone Cameo is inferior to Rakdos Keyrune and Drake-Skull Cameo will be in a few months when Dimir Keyrune is released.

They are inferior to a lot of things: the Keyrunes, Darksteel Ingot , Vessel of Endless Rest , Chromatic Lantern , Dimir Signet , Izzet Signet , Rakdos Signet , etc.

I don't actually run them though, just a thought