PROS

+ One of the best ADC's in game with hard carry potential.
+ Offers great utility with his unique kit.
+ Is never boring to play.
+ Huge outplay potential
+ Very confusing champ for enemies who don't know him well so he gets a slight advantage since they will not know what to expect.

CONS

- Very hard to master
- Lots of combos and abilities info to remember and combine to choose best weapons for each situation.
- Immobile.
- Very weak early game.
- Very team reliant for peeling

Conqueror

Conqueror is a solid option for Aphelios providing some extra AD and sustain in fights which in combination with Severum's (red gun) healing adds up a lot in fights. His kit makes it really easy to stack Conqueror and then initiate a long range trade leaving no counterplay.

Lethal Tempo

Lethal Tempo is also one of the best options for Aphelios. The attack speed it offers makes it ideal for short trades in lane and lets you have a not so predictable playstyle because since you attack faster you drain ammo faster and thus you can cycle your weapons quicker and get the one that suits best the occasion.

Overheal
You get a lot of healing in lane from Legend: Bloodline, Conqueror (if you go for it), and Severum (red gun). And when you are full hp all that healing will be wasted so why not let it build into a shield to protect you from getting bursted down. Considering he has no escape tools or defensive tools, the shield will surely come in handy.

Legend: Bloodline
Legend: Bloodline also aims at keeping you healthy throughout the game and has some outplay potential too since the healing that will add up with the other sources will surprise your opponents. Another options is Legend: Alacrity if you want to synergise it with Lethal Tempo or if Conqueror's healing is enough for you.

Coup de Grace
Pretty standard option for good burst on low enemies to finish them off.

Nimbus Cloak
Aphelios has no escape tools so when in need to pop a sum spell the movement can help you get out of a tight situation for engage even harder. Solid option in my opinion to get some mobility to be harder for enemies to corner you.

Gathering Storm
Provides some good AD the longer the game goes. Aiming at late scaling. Absolute Focus can be an option if you want to play it more like in early-mid game since with all the healing you will be getting the added AD mos of the time but not such a good option. Gathering Storm is my personal go to.

Aphelios has a lot of combos because he is a champion where the sky is the limit. You can use everything with everything and make it work in the proper situation. But here are some common ones that you want to try:

- Crescendum, the Chakram with Severum, the Scythe Pistol or with Infernum, the Flamethrower, you use Q with pistol or flamethrower and gain chakram stacks. Then switch to Chakram and start auto attacking enemies to preserve the stacks. And when they are about to expire switch again, use Q, and switch back to Chakram. It is the highest DPS weapon with auto attacks if you manage to get the stacks.
- Crescendum, the Chakram with Calibrum, the Sniper Rifle, the Q can place turrets to mark enemies and poke them from very far. Also in teamfights you can Q with chakram to place turret, switch to sniper, and q,r get a ton of chakram stacks switch to chakram again and deal lots of damage with every auto attack.
- Gravitum, the Gravity Cannon you can 5 man R and snare them with Q. Great potential for wombo combo.
- Calibrum, the Sniper Rifle with Gravitum, the Gravity Cannon, you Q with calibrum and auto attack for the mark while cannon is on your off-hand. Then switch to cannon and Q. Thus you can snare the enemies from a very long range.
- Infernum, the Flamethrower with Gravitum, the Gravity Cannon, if the enemy are grouped up you can Q with flamethrower, slow them, and then Q with cannon for multiple snares.