As part of my research on planet formation, I sometimes develop software. Some of it is publicly available through my Github account.
Pebble predictor is a Python script which lets you estimate pebble size (Stokes number) and pebble mass flux in a protoplanetary disk without substructure. In combination with a pebble accretion efficiency factor calculation, pebble predictor can be used to calculate planet growth by pebble accretion, which is one of the emerging paradigms of modern planet formation theory.
Implode is a Fotran code to simulate gravitational collapse of a bound pebble cloud driven by inelastic collisions of pebbles and gas drag. It uses a Monte Carlo algorithm to solve the collisional evolution of pebbles.