Marbles is an extraordinary module. I can't think of an equivalent, it is like no other. I often work in this way of randomization. Marbles is a sun king.
To complete, some modules to consider for a small rack: Rnd Step, Ochd; one can also think of Nano Rand, Quantum Rainbow, and some Doepfer modules including the A-118-2.
'On ne devrait jamais quitter Montauban' (Fernand Naudin).