Theme

This is a deck of distant legends and mysticism. The theme of the deck is clearly focused on Faeries, drawing heavily from the roots of the old Fish archetype in Magic: The Gathering. It’s a tempo-control deck: you annoy your opponents, deal small but consistent damage, and generate card advantage.

Strengths

Very good late game
Good card advantage and quality through toolboxes and Sylvan Splendor
High flexibility, you can switch to fast aggro o full control depending the draws
Quite good against slower control
Fast opponent's life burn once setted up
Very strong sites
Very strong card removal / control

Weaknesses

Low power minions, but some of them really impactful
Can be vulnerable to explosive early aggression
Witch can be tricky in this one
Misplays are heavily punished, often time you're gonna lose after 2 mistakes
Some combination of initial card draw can be punishing
Depends heavily on sites

Strategy

The deck kept me busy for quite a long time before I found the right build, and even longer before I learned how to use it properly. The main strategy, as I mentioned above, is to annoy the opponent, buy time early on through lands and control spells, and then burn down the opponent’s life total in a very short time.

Play only 6 sites, you don't need more. Try to be defensive, you need time.
Mulligan allways not impactful sites: you need to defend the Witch. You allways need one of these site: Bottomless Pit, Mountain Pass, Troll Bridge, Wuthering Weights. These help to keep enemy minions away.
Try to keep sites on the first row as long as possible, unless they're control sites. Don't spread too much, you need to use your Sylvan Splendor and minion/sites abilities.
Defend and kill everything the first turns. Then, when you're ready and the battlefield is stable, burn enemy life with Witch, minions in enemy sites with Spore Spouts or Summoning Spheres.
If the enemy is slower than you, and he has fewer sites, play the other ability of the Witch "pay 1 more". You're gonna tempo him fast enough.
If the enemy is an aggressive avatar like Battlemage, and he's chasing you, keep him at bay with the last Witch ability, -3 power: he will be turned off.
Use your magic to control the battlefield: Plague of Frogs to protect you Witch from aggro, Chaos Twister, Pollimorph to remove big threats, and the others to remove small threats.

Nice combos:

Lookout + Hyter Sprites: lock and tempo your opponent for 1 turn, sometimes can really save you time.
Sling pixies + Poisonous dagger: great ranged removal, very obnoxious.
Wuthering Weigths or Abbadon Succubus + Bottomless Pit or Troll Bridge, or multiple combinations of those: just have fun, while the opponent doesn't. XD
Sir Tom Thumb + Sylvan Splendor: a good blocking creature, and each time it dies you can play it again within Sylvan Splendor, generating card advantage.
Fey Changeling + Sylvan Splendor: if i understood it right, you can draw 1 card every 3 mana, targeting Fey Changeling's ability on itself.
Any Faerie + Fae City: can really be annoying, but not so easy to get it right.

Faeries Tempo

@archanz