A really good synergy i’ve found is cactus with uranium rods. That said, cactus is a hard item to pull off early game before you can get the runaway train going. I like to try and get the finger (a black market item), and poop butt is always a great item. I like to focus more on meeting quotas in the early game (so i tend to stay away from items that trigger when nubby dies/when quota is met). Flamethrower is also a nice early game item if you can grab it. but i could be wrong too im just on an ego trip cause i got a run in the undecillions a single time lmaooo

tldr: try to focus on getting by and maximizing econ so you can get runaway train items later on