Many decks that play Leyline of Anticipation also play Vedalken Orrery. The major advantage to any of the Leylines in Magic is that if you have it in your opening hand, you can put it right into play. Having every nonland card in your hand able to played at instant speed can work well in any deck. But, Blue decks in particular like to have the Flash ability, especially for their sorceries.
Another reason for Blue decks liking Flash so much is that Blue-centric decks like to keep open mana for counter-magic. If for whatever reason a counter-spell isn't required, that would be mana that's otherwise wasted. With Leyline of Anticipation, you can then cast something that you would have to usually wait for your own turn while your opponent is still going. It would be a creature or artifact that you otherwise would have to wait until your own turn to cast. Preferably, it's best to flash in cards at the end of an opponent's turn.
One deck that makes great use of this Leyline is the Commander 2015 Legendary, Arjun, the Shifting Flame. Arjun is one of the more tricky decks to play. Most of that deck's key cards are Artifacts, Enchantments, and Sorceries. Arjun favors the Leyline over the Orrery since you have a chance to begin the game with it on the field, which gives the deck a definite edge early on. It's a slow deck to begin with to set up all of the pieces, so having the Flash available is more important here than many other decks.
Other Commanders who have used Leyline of Anticipation on a regular basis include:
- Rashmi, Eternities Crafter
- Narset, Enlightened Master
- Kruphix, God of Horizons
- Oloro, Ageless Ascetic
- Damia, Sage of Stone
- Nekusar, the Mindrazer
- Mizzix of the Izmagnus
- Riku of Two Reflections
Rashmi and Narset are the most popular of these, so they are the decks typically garner most of this Leyline's demand.
Leyline of Anticipation doesn't see any regular Constructed play outside of Vintage Goblin Charbelcher combo decks. Still, it’s a really solid enchantment that has a home in many Commander decks.