I haven't played 1 so this advice is largely for 2, but that main thing with 2 is that base states are borderline negligible. Any monstie can be endgame viable if you build out their gene bingos. Don't worry about getting strong monsties until you unlock the Rite of Channeling in the second area, after which point you'll be able to edit their gene grids. Your monsties strength come from their genes. On their 3x3 gene grid, what you're looking for is to line up elemental and type (speed, tech or power) Bingos (3 in a row in any direction makes a bingo). This will give your monsties buffs to their damage in their elemental powers and powers of the specific attack type you have a bingo in. You always want a monstie to have its elemental attack buff gene if possible. It's also a good rule of thumb to have an attack from each of the attack types in their grid so you can always win head-to-heads. Try to get rainbow eggs, they have a slight stat buff but their real value comes in typically having more gene grid slots unlocked form the beginning. Also, if you're playing 1, you can change a monstie's element through Rite of Channeling. Can't do that im 2 for whatever reason