Treasure Hunter

Most rogues love treasure, but their opportunistic sense is generally too high to focus so exclusively on finding these treasures that they only pursue them when the signs pointing the way are very clear. However, there are those that go out of the way to find the largest, most hidden, most dangerous hoards and attempt to gain access to those, in particular. These capable explorers are often simply called Treasure Hunters, but the name is a misnomer for the degree of skill, dedication, and even mysticism that one must wield on their journeys throughout the realms in order to successfully find their payday. Capable cartographers, expert trap handlers, seekers of all that's hidden from prying eyes, the Treasure Hunter is not only willing and able to locate vast treasures, but also quite adept at navigating the dungeons, temples, caverns, and lands in which the best treasures lie waiting. They exhibit knowledge over many fields, and most use that knowledge to go into business for themselves, only bringing along allies when the going gets extra tough.

Archeological Expertise

When you choose this archetype at 3rd level, you gain proficiency in two of the following skills of your choice:
Arcana, History, Investigation or Religion. You also learn two languages of your choice.

Additionally, whenever you make an Intelligence (History) check related to magic items or historical artifacts, you can add twice your proficiency bonus, instead of any proficiency bonus you normally apply.

Finally, you can attempt an Intelligence (History) check to decipher any written dead language you don't already know.

Arcana

Proficiency in Intelligence (Arcana)

History

Proficiency in Intelligence (History)

Investigation

Proficiency in Intelligence (Investigation)

Religion

Proficiency in Intelligence (Religion)

Whip Mastery

Also at 3rd level, you gain proficiency with the whip. As an action, you can use this weapon almost like a third hand, to perform feats like punch a button, retrieve an unattended object, and firmly wrap the end of your whip around a pole. You can also use your whip to disarm at range (see DMG 271).

Furthermore, you can use your whip to trip a creature: this works as shoving a creature (see PHB 195), except that you must make an attack roll with your whip instead of a Strength (Athletics) check, and that you can only knock the creature prone or pull it 5 feet closer to you (instead of pushing it away).

Grappling Whip

Starting at 9th level, you can perform a grapple at range (see PHB 195) using your whip. This works like a normal grapple, except that you must make an attack roll with your whip instead of a Strength (Athletics) check and that, if you succeed, you immediately drag the grappled creature within 5 feet of you.

Use Magic Device

By 13th level, you have such deep knowledge of mystical artifacts and ancient magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of magic items.

Spell Resistance

Starting at 17th level, you have advantage on saving throws against spells.

Furthermore, you have resistance against the damage of spells.