How does one get sprites into a static class?

I have a set of tiles. Each of these tiles has a number attached called the sprite index. When reading these tiles to place them into the world, I take that number and use it to look up a sprite from a scriptable object which holds an array of sprites, called a sprite pallet. I need to access a pallet from the static class that holds the map generation. I also need to be able to set that pallet beforehand and to put sprites in it somehow. I can do one or the other, but not both. I either have a palate I cant use or a sad empty palate that holds no sprites

I have tried making a mono behavior that has an instance variable that is hooked up with get/set into a static class with an array of pallets but It does not show up in the editor, making it rather hard to assign pallets to.

Does anyone know a good way of getting premade, persistent objects, be they scriptable or image-based, into a static class?

I don’t know how much the code will help with this question, but here it is, just in case

public class Map 
    //map data
    public int sizeX;
    public int sizeY;
    public int spritePallate;
    public float[,] heightMap;
    public bool[,] walkableMap;
    public int[,] spriteIndexMap;

public static class MapReader
  public static Tile[,] GeneratePhysicalMap(Map map)
        if (map == null)
            map = new Map(backupMapSize.x, backupMapSize.y);
        tileParent = new GameObject("Tile Parent").transform;
        tiles = new Tile[map.sizeX,map.sizeY];
        Vector2 mapHalfHeight = new Vector2(map.sizeX / 2.5f, map.sizeY / 2.5f);
        for (int x = 0; x < map.sizeX; x++)
            for (int y = 0; y < map.sizeY; y++)
                Tile tile = map.SetTileProperties(x, y);

                GameObject gameObjectTile = InstantateTileGameObject(mapHalfHeight, tile);

                gameObjectTile.AddComponent<TileBehaviour>().tile = tile;
                tiles[x, y] = tile;

                gameObjectTile.AddComponent<BoxCollider>().size = new Vector3(1, 1, .2f);

                gameObjectTile.AddComponent<SpriteRenderer>().sprite = GetSpriteFromIndexAndPallete(tile.spriteIndex,/*ERROR*/);
        return tiles;

    public static Sprite GetSpriteFromIndexAndPallete(int spriteIndex, SpritePallate spritePallate)
        return spritePallate.sprites[spriteIndex];

[CreateAssetMenu(fileName = "Pallate", menuName = "SpritePallate", order = 0)]
public class SpritePallate : ScriptableObject
    public int ID = 0;
    public Sprite[] sprites;

If you’re calling GeneratePhysicalMap from a GameObject, you could make the SpritePallate a parameter of the GeneratePhysicalMap method. The GameObject could then store a reference to a SpritePallate and pass it to the method when it is called.

public static Tile[,] GeneratePhysicalMap(Map map, SpritePallate spritePallate)