Tactician

Its kind of obvious what you get with this subclass.

Planned Attack

Beginning when you choose this archetype at 3rd level, your weapon attacks will gain advantage to hit if you are the first to act in combat.

Detect Weakness

Starting at 7th level, you can now take an action to target a creature and make an insight check on the creature (The DC for the check is equal to 10 + the targets wisdom bonus), and succeeding will allow you and all PC's within 30 ft of the target to deal an extra 1d8 damage to the target creature.

At higher levels. Every 4 levels after unlocking this ability increases the damage by 1d8, level 11 2d8, level 15 3d8, level 19 4d8 .

Additional Fighting Style

At 10th level, you can choose a second option from the Fighting Style class feature.

Archery

You gain a +2 bonus to attack rolls you make with ranged weapons.

Defense

While you are wearing armor, you gain a +1 bonus to AC.

Dueling

When you are wielding a melee weapon in one hand and no other weapons, you gain a +2 bonus to damage rolls with that weapon.

Great Weapon Fighting

When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll, even if the new roll is a 1 or a 2. The weapon must have the two-handed or versatile property for you to gain this benefit.

Protection

When a creature you can see attacks a target other than you that is within 5 feet of you, you can use your reaction to impose disadvantage on the attack roll. You must be wielding a shield.

Two-Weapon Fighting

When you engage in two-weapon fighting, you can add your ability modifier to the damage of the second attack.

Patient Tactics

Starting at 15th level, you can pass your turn to gain one of 2 effects (And only one at a time) -

1 - you can attack as a reaction to someone entering 5 ft of you or attacking you
2 - you have resistance to non-magical melee or ranged attack (choose one of the two) for the rest of the round.

Ready Arms

Starting at 15th level, you can pass your turn to gain one of 2 effects (And only one at a time) -

1 - you can attack as a reaction to someone entering 5 ft of you or attacking you
2 - you have resistance to non-magical melee or ranged attack (choose one of the two) for the rest of the round.

This does Not count as an action

Foresight Tactics

At 18th level, you attain the pinnacle of tactics in battle. 

You can predict the movements of your enemies and plan to fight against them. you can now have these effects permanently 

you cannot be surprised
you can now use your reaction to make ranged attacks
all attacks have disadvantage against you