>>42674421don't forget Jade Cocoon, which had an entire pedigree system; your creature had a body type and a skin type, and half the elemental attributes of each. And each body type had key features that both passed on, stacked, and got bigger with maturity/level.
So for example if you took the horned dog body and fused two of the same together, the horn on the offspring would be bigger; if you took one and just leveled it up the horn would also get bigger, as would the horn trait it would pass down to its offspring; and if you bred it with something without a horn, the offspring would develop the start of one. elemental properties came in 100, 75, 50, and 25% increments, cutting in half and stacking based on breeding. Body posture also passed down, so fusing a humanoid ogre into something like a 4-legged canine would cause the dog body to start standing upright, or for the ogre body to lean forward, depending on the main and subtype.
It was graphically pretty rough, being a 90s ps1 game, but the actual algorithmic and programming behind it was super clever.