Potions heal for a small amount instantly and you move faster while being healed by them.
Offense
+5 AD or 9 AP
Flex
+6 Armor or 8 MR (match-up)
Defense
+15-90 Health
WhySummon Aery
Singed's repetitive damage from [Q] allows you to constantly proc Aery over and over for a strong amount of bonus damage throughout the game.
WhyNimbus Cloak
Nimbus Cloak has a fantastic synergy with Singed, granting you a massive amount of Movement Speed so that you're able to either hard-engage for a kill or run away to survive.
WhyCelerity
Singed is naturally a Movement Speed based champion and thus Celerity synergizes well with his playstyle as well as Time Warp Tonic and your natural Movement Speed.
WhyScorch
Like Aery, Scorch synergizes well win Singed's constant poison damage allows you to chip away at your opponent as you run circles around them.
WhyBiscuit Delivery
Biscuit Delivery massively buffs your ability to take aggressive drawn-out trades and sustain through the incoming damage. They also synergize well with Time Warp Tonic
WhyTime Warp Tonic
Time Warp Tonic is perfect when paired with Dark Seal on Singed, granting you a ton of extra Movement Speed and sustained healing.