They essentially allow for an extra land drop when in an opening hand, and allow for early ramp that is reusable the entire game
Cards featuring popular characters, with strong visual impact, and where demand concentrates easily, tend to come out on top

Animar, Soul of Elements Avalanche Tusker Averna, the Chaos Bloom Bear's Companion Beluna Grandsquall Beluna Grandsquall Borborygmos and Fblthp Dragonback Assault Dragonclaw Strike Eshki Dragonclaw Eshki, Temur's Roar Flubs, the Fool Genesis Ultimatum Genesis Ultimatum Gimbal, Gremlin Prodigy Guided Passage Illuna, Apex of Wishes Illuna, Apex of Wishes Intet, the Dreamer Iroh, Grand Lotus Kalamax, the Stormsire Karakyk Guardian Loot, the Key to Everything Loot, the Pathfinder Maelstrom Wanderer Magus Lucea Kane Mammoth Bellow Me, the Immortal Miirym, Sentinel Wyrm Omnath, Locus of the Roil Pia Nalaar, Chief Mechanic Rashmi and Ragavan Riku of Many Paths Riku of Two Reflections Roar of Endless Song Saheeli, Radiant Creator Sarkhan Unbroken Savage Knuckleblade Snowhorn Rider Song of Creation Songcrafter Mage Storm, Force of Nature Surrak Dragonclaw Temur Ascendancy Temur Battlecrier Temur Charm Temur Tawnyback The First Tyrannic War The Swarmlord Trap Essence Ureni of the Unwritten Ureni, the Song Unending Xyris, the Writhing Storm

How many cards are in a Temporal Forces master set