I’ve been using Nik’s software suite for a few years now. The suite has several different modules, but I spend most of the time in Silver Efex Pro II. Within that module there are several different ways to process your color images. There are a couple dozen presets, there are tools for manipulating your image manually and then there are a set of film simulations.
Currently, the Kodak 100 TMAX Pro simulation is my favorite. It’s quite contrasty and adds a very small amount of fine grain. The images in this post were converted from raw files from the Sony RX1r and Ricoh GR.