The Your Best Friend pact is one that is very rarely ever seen in existence and in actuality the user of such a pact lacks several Warlock abilities, not being able to cast the spells on their own but requires their best friend to cast it while behind them. The user will never actually learn on their own that its their Best Friend though those around the user may find out but the Best Friend will do their best to conceal it, having invisibility spells and such.

Expanded Spell List

Due to your pact actually being Your Best Friend who has studied magic and became a wizard in order to help you it means you have access to not just Warlock spells but Wizard spells as well. This includes the entirety of the Wizard spell list up to Level 3.

Fake Caster

As you are not an actual caster, lacking any proper magical abilities and Your Best Friend is just helping you, you do not need to do any Verbal or Somatic casting. Meaning the only thing you must worry about is the material components. However there is a drawback to this as anything requiring any currency for casting will have an added +5 gold pieces per level of spell.

Best Friend's Help

Due to Your Best Friend cooking you some very good food but acting like your patron made it then after a long rest you will get 1d4+CHA Modifier temporary hit points (this doesn't stack with other temporary hit points), however to do this you must be long resting in a place where a fire may be started and you are long resting somewhere there is at least a 30x30 ft. area to cook food. You must complete a full Long Rest to do this. (At 3rd level roll a 1d6, 6th level 1d12 and 12th level 1d20 which is when it maxes out.)

Two Casters

By sacrificing your Bonus action you can cast two spells on your action, first you cast a spell of any level but after that you cast a spell from Cantrip to Level 1. This can be used in another way however, how this is done is that by sacrificing two charges of this spell you can cast three but two must be on the Warlock Spell list and have to be Cantrip to level 2 (cantrips are used at their weakest damage levels) and the third has to be a Wizard Spell.

Combined Casting

Your Best Friend begins to direct you how exactly to use powerful magic. When you're using this feature you have to use any somatic or verbal spells yourself and upon using it then you can give up your bonus action and reaction to upgrade the level of a spell, increasing the damage or effect along with also having its range (if it has any) be increased by 10 ft. This can be used only once per long rest. There is no level cap for a spell of this, meaning if you make it to when you get 9th level spell you can get it to become 10th level, a spell stronger than all which will let you double the damage dealt (if it does damage.).

The Best Friendship Ever

Upon reaching 14th level the user can use this feature. This feature gives the user proficiency in two of any saving throws (of the user's choice, mark this down in notes and inform the Dungeon/Game Master which two.) per long rest along with two other options. As a passive upon gaining this ability the user gets an increase of temporary hit points equal to your level (this is the one thing that stacks with the temporary hitpoints gained from a long rest.). Finally the last ability grants the user the ability to lower the death saving throw from 10 to 5, meaning you only have to get a 5 or higher to succeed on a death saving throw.