upgrade.json

{
    "forge_marker": 1,
    "defaults": {
        "model": "extragenarators:item/upgrademodel"
    },
    "variants": {
        "speedboost1": [
            {
                "textures": {
                    "layer0": "minecraft:items/coal"
                }
            }
        ],
        "speedboost2": [
            {
                "textures": {
                    "layer0": "minecraft:items/egg"
                }
            }
        ],
        "speedboost3": [
            {
                "textures": {
                    "layer0": "minecraft:items/emerald"
                }
            }
        ],
        "speedboost4": [
            {
                "textures": {
                    "layer0": "minecraft:items/clay_ball"
                }
            }
        ],
        "powerstore1": [
            {
                "textures": {
                    "layer0": "minecraft:items/carrot"
                }
            }
        ],
        "powerstore2": [
            {
                "textures": {
                    "layer0": "minecraft:items/cake"
                }
            }
        ],
        "powerstore3": [
            {
                "textures": {
                    "layer0": "minecraft:items/bread"
                }
            }
        ],
        "powerstore4": [
            {
                "textures": {
                    "layer0": "minecraft:items/bowl"
                }
            }
        ],
        "multiplier1": [
            {
                "textures": {
                    "layer0": "minecraft:items/bed"
                }
            }
        ],
        "multiplier2": [
            {
                "textures": {
                    "layer0": "minecraft:items/hopper"
                }
            }
        ],
        "multiplier3": [
            {
                "textures": {
                    "layer0": "minecraft:items/bone"
                }
            }
        ],
        "multiplier4": [
            {
                "textures": {
                    "layer0": "minecraft:items/diamond"
                }
            }
        ]
    }
}