BMF.io doesn't clearly list which types of businesses can't join their company membership. But usually, places like this don't allow shady or sketchy businesses , like ones selling illegal stuff, promoting scams, or using super misleading marketing. Also, if they're involved in anything that's banned or under legal trouble, that's a no-go too. But honestly, if your business is legit and you're not trying to trick people or break the law, you're probably good.