or yeah maybe if you come across the seed type in a run then it becomes available to the beginning of the game selection.
This is tough cause I feel like I personally have an optimal strategy or specific seeds that I feel in combination are a bit overpowered, especially towards the top of the mountain. Maybe it's a matter of balancing those abilities, but yeah I do like having to deal with what your dealt, and I wonder if that gets lost when letting players just choose the starting seeds.
Or maybe you can choose X suits (up to 4) and you incur some kind of debuff like seeds costing more. There's a lot to consider/toy with here!