Further Upgrades The first cards I'd pick up to further juice up the deck would be untapped mana-fixing lands: Watery Grave, Shipwreck Marsh, Underground River, Morphic Pool, Darkslick Shores, Polluted Delta, Sunken Ruins, Undercity Sewers, Urborg, Tomb of Yawgmoth and then maybe a couple more Island / Swamp fetches
Anytime any player draws their second card each turn, they then have to exile the top card of their library
Likewise, Orchish Bowmasters is a great new black EDH staple that does the same kind of work here as Lotho, namely via punishing opponents who are trying to do too much by pinging any target and providing creature tokens that can end up doubled if you dont already have one
Warner: Cautiously optimistic