Two things; D-76 is a fine grain developer, and it tends to hide the grain; grain is an inherent part of the film, and there is little you can do to increase it. Selecting a developer like Rodinol (or maybe DK-50) will make the grain apparent, but modern films are still very fine grained. The idea of taking the picture with high enlargement in mind and then using a non-fine grain developer seems to work, at least to some extent (you get into fuzziness problems). An old technique was to print with a texture screen sandwiched with the negative. You used to be able to buy a selection of texture screens, including some for enhanced grain effects, pretty cheaply, but I haven't seen them on the market for about 35 years. Perhaps a reader knows how to make one.