Summoner Spell cooldown abuse for aggressive picks with Flash->[R].
Creative tools and rule bending
Swap Summoner Spells while out of combat. Swapping to unique Summoner Spells will increase the rate at which you can make future swaps.
Gain a free stopwatch. Stopwatch has a one time use Stasis active.
Start the game with 6 Minion Dematerializers. Killing minions with the item gives permanent bonus damage vs. that minion type.
+5% Max CDR
+5% Summoner Spell CDR
+5% Item CDR
+22 Ability Power or +13 Attack Damage, Adaptive
Gain 3% extra MS. Gain extra AP or AD, based on your bonus MS, Adaptive.
Your first ability hit every 20s burns champions.
Unsealed Spellbook allows you to heavily abuse your Summoner CDR with Lucidity Boots for aggressive picks with Flash->[R].
It also allows you to swap between Cleanse/Ghost and TP for when you need lane pressure.
Perfect Timing is a great rune in situations where enemy mid has dive potential on you and you want to make the out-play.
It also allows you to buy an earlier/cheaper Zhonya's or just sell off the Broken Stopwatch for the free gold.
Minion Dematerializer on Malzahar is great for empowering your ability to wave clear for optimal recall timing and roams to the side lanes.
The extra bit of CDR and Summoner CDR from Cosmic Insight even further enables your potential to abuse your short Flash cooldown.
The extra bit of Movement Speed from Celerity comes up big when just outside of range for a well-timed ult.
Scorch provides fantastic early-game lane pressure for poke and harassment so that you're able to keep the enemy in kill range when you hit level 6.
Patch 8.10 saw a buff to Phase Rush and jungle duels for scuttle making Xin a powerhouse.