Can a pantheist believe in the law of attraction? Sure! But it certainly isn’t required.
For pantheist pagans, I imagine there’s a greater chance of believing in things like the law of attraction, crystal healing, and reincarnation, but there’s no dogma within pantheism or even paganism that tells you which of these things to believe in, if any.
Pantheism and paganism are merely jumping off points that often intersect, so as a pantheist pagan, you may find yourself trying to develop your own practice that makes sense in terms of your unique worldview.
With that being said, I’ve been contemplating the law of attraction a lot lately. In my pagan practice, I perform rituals that might not necessarily make sense to a strict naturalistic pantheist, but that’s okay. Sometimes my own rituals don’t even make sense to my rational mind! But I always focus on the intention behind them and the type of energy I want to put out into the universe. Performing a ritual is a type of meditation for me—a way to ground and reconnect with myself.