You might be able to drop a Mana Leak for another Familiar's Ruse? Also why do you have four Mutavault? I feel like Creeping Tar Pit might be better... Also have you thought of adding Sword of Fire and Ice? The draw could be really helpful. Love the deck by the way! You did a great job here.

I do want another Familiar's Ruse but currently only own one, but I have a couple more in the mail so I will be making the change. I chose Sword of Light and Shadow for life gain and the ability to return a creature from my graveyard to my hand, and this is particularly beneficial to get back Spellstutter Sprite or Snapcaster Mage, but being able to get any creature is beneficial in this deck. Drawing a card is nice but having a choice from my graveyard feels better. Every time I've got that sword out and equipped I've won the match, so it feels quite useful. I went with a full play set Mutavault because it plays nicely with Scion of Oona. I could play another Creeping Tar Pit but don't like the idea of having to many lands that come in tapped.

A playset Of mutavualt seems too much. 4 colorless lands when using a cryptic and vendillion is not advisable. Id cut two of them for one more Creeping Tar Pit and maybe a basic. Mainboard I feel you can cut two Scion of Oona for more removal because 15 creatures when you run 4 Bitterblossom is not necessarily a good thing. Plus oona be the only creature they can counter so might as well reduce the number. I would add more Spell Snare or consider a Threads of Disloyalty to use as a goyf stealer.

I've never actually had an issue with having the right mana on hand to cast Vendilion Clique or the Cryptic Command and have even used Snapcaster Mage to target a Cryptic Command a couple times. If I dropped the Scion of Oona I would probably opt to play Sword of Fire and Ice in its place. There really is not a need for more counter spells, but probably more of a need for the swords being consistently found. Also, I have not lost a match where a sword has been equipped. I'm a little skeptical of the need to drop Mutavault because I have not had an issue with it before and I tend to dislike playing lands that come into play tapped. If I dropped the Scion of Oona completely I would drop the Mutavault too.

Drop Mutavault for x2 Darkslick Shores x2 Watery Grave?

Maybe drop all four Scion of Oona for x1 Cryptic Command, x1 Familiar's Ruse, and x2 Sword of Fire and Ice. I also love the Threads of Disloyalty idea. That would be a great sideboard card.

I made an alternate list with cards I have removing the discard completely and some of the other suggestions. Here is the link Modern Faerie Deck v2. I may try to play this version tomorrow at my LGS to see how it is.