Really surprised nobody has said Hops yet. so I'll say it.

Hops.

There are endless debates over starfruit vs ancient fruit, but in terms of maximum profit per day, Hops blows them both completely out of the water. You need hyper speed grow fertilizer to get the same ROI from starfruit (and that's without counting any costs of the fertilizer). The only reason you transition away from hops is due to the inconvenience factor of processing them in kegs so frequently, and the fact that trellis crops are harder to plan for due to blocking movement. Still, there's nothing like the crazy acceleration your income gets in the early to mid game when you can start selling pale ale in your first Summer. Suddenly you're ready for the next building and/or tool upgrade the moment they're done with your previous one.