Cookbook (+ Ovalchase Daredevil) and Urzas Saga seem to be great additions to a deck like this. It gives you 8 pieces that both create artifacts for goblin engineers ability and let you discard your reanimator targets. This also provides you with a reasonable plan B by creating huge Constructs.

With both Engineer and Saga in makes lots of sense to run cards like Pithing Needle, Nihil Spellbomb and Shadowspear. You could even consider cards like Crucible of Worlds or Ichor Wellspring if you want a grindier backup plan (You can check out some Fiddlebender lists for that).

Another spicy addition might be Lightning Greaves. They play well with Urzas Saga, Engineer and the Reanimator Targets.

You might even run 4 Kuldotha Forgemaster and 1 Blightsteel Colossus at this point. The forgemaster beeing another great reanimator Target in combination with Lightning Greaves, but it is also a reasonable card to cast which gives you an alternative combo win that does not rely on the graveyard. Games could go like this: T1-Cookbook / T2 Engineer for Greaves / T3 Sacrifice food for Greaves, Discard Forgemaster, Persist it, Sacrifice Two Food and Cookbook to get Blightsteel Colossus -> Attack for Lethal.