The Balrog of Moria lets you set up Sauron in more ways than one, helping to ramp into our commander with some treasures while providing a premium reanimation target when the Dark Lord is actually cast
Both of these can sacrifice our tokens to bring back artifacts we lose
Not really for me though I think, I just am not putting the puzzle pieces together on why you want to make a colorless manifest deck
After playing a bunch of matches with the deck, I'd say that we choose to make Servos about 95% of the time with both of these cards, with the only real exceptions being very obvious (for example, an opponent has a Liliana, the Last Hope that will immediately kill our Angel of Invention if we don't put the +1/+1 counters on it)
A Three Visits or Natures Lore does the trick, but expensive rocks such as Mox Diamond and Chrome Mox will help get the job done faster
It turned out to be a much easier task than Tribal Elephants, so that's nice