So I was reading through my old posts cause I wanted to read through my old champion concepts and I found an old post for a suggestion on an inspiration keystone. Since Omnistone doesn't look like it's really gonna have any place in the meta I wanted to share the idea again.
Basically this keystone would work like LeBlanc's clone when she was reworked. You can spawn in a clone of your champion anywhere on the map (or maybe within some range). This clone will walk towards the nearest visible enemy champion and cast your last used basic ability on that enemy. This ability will deal no damage. It's simply all about the trickery and mind games.
I think this'd be a very fun keystone and work decently well on some champions. Mainly assassins and supports, or anything that's effective at ganking. You will be giving up the power of a different keystone for this trickery, but Inspiration generally has just been a very situationally effective rune page since forever now anyways, so why not add a fun keystone like this?