The Collector

Your patron is a dragon or other powerful hoarding monster. their intentions are focused on the collection and storing of valuable items and this will often affect those that a pact has been made with. other than that will depend on the creature that the pact is made with. some examples of such creatures and Dragons, Sphinxes and Manticores

Hoarders sight

Your patron's love of gold and valuable things is passed on to you through a deep urge to protect what is yours, lest others attempt to steal it from you.

You gain advantage on ability checks against anything trying to steal your possessions or gold.

Expanded Spell List

your patron grants you extra spells to choose from.

Secret stash

You open a portal to a plane of storage where you keep all of you valuables and gold. however, you become unable to trust other, more conventional storage methods and find it near impossible to part with possessions, except with your closest of friends.

you are able to cast the spell Demiplane without expending a spell slot. 

You can only use this ability once per short rest.

Hidden opening

your connection to your treasure allows you you to remove it from it's place of storage without opening it, lest pesky theives sneak in and steal your shinies. you are no longer able to open you secret stash in front of people you do not consider to be close friends.

 

You select one demiplane that you can access, this becomes your secret stash. you are then able to extract one item of small or smaller size from your secret stash without opening it this happens with a small flash of light that is a colour of your choice. If you wish, you can also expend 2 uses of this ability to send 1 item of small or smaller size into your stash. If you wish to switch your stash to another demiplane it requires a 1 hour ritual that can be performed during a short or long rest.

you can use this ability a number of times equal to your charisma modifier per long rest.

Snatching grasp

your connection with treasure has become so great that it comes to you at your will. you are now so affixated with treasure that you automatically attack anyone who touches your treasure, friend or foe, without your explicit permission.

you can teleport one item of tiny or smaller size into your hand. if it is being held by a sentient creature then that creature must make a wisdom saving throw against your warlock dc to hold onto the item. whether they succeed or fail the creature is alerted that the item is missing. 

this ability can be used once per long rest.