RENEKTON

Defensive:

Force of Nature This is a must have against heavy caster teams.

Banshee's Veil This is good against mixed, balanced teams with a slight leaning towards magic damage.

Sunfire Cape Great against physical enemies. Deals damage well in conjunction with Dominus.

Thornmail If they have a squishy physical carry, i.e. Ashe, Tristana, etc., feel free to ruin their day by getting this.


Offensive:

Stark's Fervor Armor reduction, life steal, attack speed? A nice overall team buff. No AD to scale with your abilities, however.

Hexdrinker If casters are ruining your day, grab this.

Last Whisper Grab against armor stacking teams.

Madred's Bloodrazor Grab against health stacking teams.

The Black Cleaver Synergizes with Ruthless Predator.

The Bloodthirster One alone will give you 100 AD if you max it. That is so good for your 3/4 AD scaling abilities.