There are infinite combos that outright win you the game, like with Walking Ballista, but Heliod can be a centerpiece of devotion decks, +1/+1 counters, lifegain decks, and enchantment-based decks
Madison Li Dragon Breath Dragon Fangs Dragon Scales Dragon Wings Dreams of the Dead Drownyard Temple Eiganjo Dynastorian Elspeth Conquers Death Emerge from the Cocoon Emeria, the Sky Ruin
Selvala's Stampede is only fun when you get to play mind games with the table and bluff that you have many more threats in your hand than you let on
4-5 Optimized and CEDH (all combos are allowed) All combos are allowed
You can use Yuna, Hope of Spira, to reanimate them for free with a finality counter, or Rydia, Summoner of Mist to reanimate them by paying their mana cost
Like most Magic: The Gathering cards, the value of Summon: Good King Mog XII depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Final Fantasy Commander)