Moloch and Proxima are actually the same species, believe it or not.
Sabaac and its fluxing cards were actually invented for the L. Neil Smith Lando Calrissian books (which were given several Easter eggs in the movie proper), although the RPGs and other tie-ins ran with it.
The game was first canonized in the New Dawn novel and we saw a paper cards version played in the Rebels episode "Idiot's Array." According to reference materials, Han and Lando play a version called "Corellian Spike" Sabaac (which had been established before the movie was played). While not seen in the movie proper, tie-ins have established that the game uses dice and that Han used his set from the movie (and previously seen in ANH and TLJ) during that final game off camera.
The Wook claims that the digital fluxing version from Legends also exists in canon, although they cite a replica playable game deck given at a convention years ago, so I do question the validity of the source, although there's no reason that digital and paper Sabaac can't coexist.