These are two options for PC and NPC warlocks for extra flavor in various campaign settings.
Pact Of The Mantle
You have a special cloak granted by your patron called a Mantle of the Night. While you are wearing your Mantle of the Night, you have proficiency with Constitution saving throws. In addition, while wearing your Mantle of the Night, you do not suffer any of the effects of hunger, thirst, pain, lack of sleep, or exhaustion except when it would cause you to die.
If you lose your Mantle of the Night, you may perform a 1 our ceremony to recreate it. You can choose the mantle's length and whether it has sleeves or a hood when recreating it. This cermony can be performed during a long or short rest and destroys the previous mantle. The mantle also fades away into a wisp of dust when you die.
Pact Of The Rod
You can use an action to create your pact rod in an empty hand. When the rod is in your hand, you can cast a spell in your patron's expanded list using a warlock spell slot. This spell must be of a spell level you can normally cast as a warlock. After you use this feature, you can't do so again until you finish a short or long rest.
You pact rod disappears if it is more than 5 feet from you. It also disappears if you use this feature again, if you dismiss it (no action required), or if you die.
New Eldritch Invocations
Mantle Of Dark Steel
Prerequisite: 9th level, Pact of the Mantle feature
You can as a reaction action choose to make your donned Mantle of the Night stiff and hard as steel. Doing this gives you resistance to bludgeoning, piercing, and slashing damage, but your speed is halved and melee attack rolls against you have advantage until the end of your next turn.
Mantle of Vigor
Prerequisite: Pact of the Mantle feature
While you are donning the Mantle of the Night, you maximum hit points is increased by a number equal to your warlock level. Additionally, whenever you gain temporary hit point, you gain additional temporary hit points equal to your Charisma modifier (minimum 1).
Rod of Harvest
Prerequisite: 5th level, Pact of the Rod Feature
When you are the closest hostile creature to the target of a spell cast with your pact wand, you have a +2 bonus to your spell attack rolls and spell DCs with that spell.
Rod of Pain
Prerequisite: 5th level, Pact of the Rod Feature
You can wield your pact rod as a one handed weapon. You are proficient with it and counts as magical for overcoming resistances and immunity to nonmagical attacks and damage. Your pact rod deals 1d6 bludgeoning damage plus psychic damage equal to your warlock level.
Pact Of The Mantle
You have a special cloak granted by your patron called a Mantle of the Night. While you are wearing your Mantle of the Night, you have proficiency with Constitution saving throws. In addition, while wearing your Mantle of the Night, you do not suffer any of the effects of hunger, thirst, pain, lack of sleep, or exhaustion except when it would cause you to die.
If you lose your Mantle of the Night, you may perform a 1 our ceremony to recreate it. You can choose the mantle's length and whether it has sleeves or a hood when recreating it. This cermony can be performed during a long or short rest and destroys the previous mantle. The mantle also fades away into a wisp of dust when you die.
Pact Of The Rod
You can use an action to create your pact rod in an empty hand. When the rod is in your hand, you can cast a spell in your patron's expanded list using a warlock spell slot. This spell must be of a spell level you can normally cast as a warlock. After you use this feature, you can't do so again until you finish a short or long rest.
You pact rod disappears if it is more than 5 feet from you. It also disappears if you use this feature again, if you dismiss it (no action required), or if you die.
New Eldritch Invocations
Mantle Of Dark Steel
Prerequisite: 9th level, Pact of the Mantle feature
You can as a reaction action choose to make your donned Mantle of the Night stiff and hard as steel. Doing this gives you resistance to bludgeoning, piercing, and slashing damage, but your speed is halved and melee attack rolls against you have advantage until the end of your next turn.
Mantle of Vigor
Prerequisite: Pact of the Mantle feature
While you are donning the Mantle of the Night, you maximum hit points is increased by a number equal to your warlock level. Additionally, whenever you gain temporary hit point, you gain additional temporary hit points equal to your Charisma modifier (minimum 1).
Rod of Harvest
Prerequisite: 5th level, Pact of the Rod Feature
When you are the closest hostile creature to the target of a spell cast with your pact wand, you have a +2 bonus to your spell attack rolls and spell DCs with that spell.
Rod of Pain
Prerequisite: 5th level, Pact of the Rod Feature
You can wield your pact rod as a one handed weapon. You are proficient with it and counts as magical for overcoming resistances and immunity to nonmagical attacks and damage. Your pact rod deals 1d6 bludgeoning damage plus psychic damage equal to your warlock level.