Ekko + Zilean = Time Tag

Imagine if Ekko's time skill affected items or buffs from other champs. So if Ekko was an assassin, Zilean uses ulti, Ekko goes in, kills enemy ADC, gets killed revives by Zilean, uses Ulti, reapplies Zileans Ulti, kills enemy APC, gets focussed by tank and jungler, gets revived again by Zilean's ulti, kills support (or least tanky champ) dies again "ARCH ANGEL" at this point, if you can't kill whoever is left, or for some reason, it is just you and ZIlean fighting you've done something horribly wrong, but if Ekko's ulti rewinds items, AND has a low CD like Kassadin's then guess what, Ulti again to reactivate Arch angel. At this point your opponents only have AA's to keep fighting, and as they try to run, you still have group stun and speed boost Zilean at hand :D

This is just one example of how is Time skill could be used, and that's in a scenario where it only affects buffs and items, if it affects enemies or allies, position or damage or even summoner spells, then it could be taken SOOO much further