Banishing/binding
Spirits/ghosts
Ancestors
Protection
Honouring death
Charging talismans
There is a taboo against black candles for their association with black magic.
Despite the stigma around using black candles for their association with being used to cast hexes and dark magic, black candles can absorb negativity and be used for protection. They are also useful for spells involving the dead and even just burning them for mourning and help with the grieving process. Likewise, if a dead one is haunting you (not necessarily literally), or someone living is causing you grief or stress, black candles can be useful in spells of banishing or binding someone, or even the negative energy itself.
When I was in highschool, I cast a spell of biinding against a girl who was making my life a hell, and afterwards, the most she would do was glare at me, and she never came closer than a few meters. This is not to be confused with dark magic. The spell caused her no intentional harm, and simply forbade her from causing any harm to me. However, if the intent was to harm another being... 'What ye send out comes back to thee, so ever mind the rule of three'.
You should always have pure intent when casting magic, or doing anything, for that matter. Never do anything to hinder others; it should be about helping yourself.