Murktide Regent is just a big dumb flying creature, but its really good at being big, dumb, and flying
Not a reliable one though, given that it's really only effective in games where you're already winning your coin flips anyway, in which case you're probably doing fine without this enchantment
Summon: Fenrir is an ideal ramp spell for Saga Tribal because it has similar utility to Rampant Growth (which is a top staple) at I, while its other abilities are less relevant, but also useful
The Fire Crystal certainly seems the best of the bunch in a vacuum, thanks to offering effects that are interesting for a multitude of different strategies
That realization has not shifted to Historic yet, but it will
Most famously, Collector Boosters feature the colored versions of the Traveling Chocobo cards, the iconic bird mounts from FF, each trading for a couple thousand dollars