Adding some things to better support blink/flicker shenanigans.

White:

Dauntless River Marshal is a great roleplayer in decks, but flounders outside of that shell. While it may make a comeback in the future, for now it will be taking a rest while Shepherd of the Flock fills in. A relevant body with a relevant upside for decks that like shenanigans should play nicely.

Blue:

Another flicker classic, Ghostly Flicker makes its way into the cube with this update. the unlucky card that makes its way out is Flash of Insight. Not a bad card by any means, and, again, may make its way back in at a later date if cantrip density proves to be too low.

On the blink front in blue, Barrin, Master Wizard is coming in to replace Prognostic Sphinx, a difficult to remove but relatively boring control win condition.

Faerie Impostor originally made its way into the cube to support the blink/flicker deck (and because the foil looks lovely), but has proved itself to be massively underwhelming. Sorcery speed on the return and the fact it can't be played on an empty board (or really anywhere close to the early turns) hurt more than it can take. It's being replaced with Mothdust Changeling for now, as an early drop that interacts favorably with the wide assortment of disparate lord effects, such as Feline Sovereign and Thunderbreak Regent.

Atrifacts:

Erratic Portal makes its way in as extra support for the blink deck. It edges out the ok Skinwing.

Akroan Horse is a good token generator that can pump out a lot of value in fodder until your opponent can manage to get rid of it, but getting rid of the pony is easier than ever with the plethora of new sacrifice effects. It has been replaced with an artifact that gives tokens in a more immediate manner (and plays better with Welder), Precursor Golem.