What are some examples of human cells that produce proteins for exportation? Which cytoplasmic organelle is expected to be well-developed and abundant in those cells?

Specialized cells of the glands, like the Langerhans cells of the pancreas (that produce insulin) or the saliva-producing cells, are instance of secretory cells. In cells specialized in secretion, the endoplasmic reticulum and the Golgi apparatus are well-developed as they participate in the storage and processing of proteins for exportation.

Protein Synthesis - Image Diversity: secretory cells