Deluge Virtuoso Ive always been a fan of Frost Lynx
It's very strong in multiplayer since you are more likely to be running at least one opponent with Green ramp and two-drop ramp spells like Rampant Growth and Farseek are getting added to ramp brews in Commander over conventional ramp like Cultivate and Kodama's Reach, so on the turn you have three mana, one player casting a two mana ramp spell with an extra land is pretty likely, and if not, then someone probably cast Explore spells or dropped an Exploration and an extra land or two
Deadly Rollick might not be the best of the Commander free spells (that would be Fierce Guardianship), but it still feels devastating when you cut off somebodys combo or remove their best creature with no mana
Its gameplan is simple but deadly: Stick a beatstick, push for damage, and force your opponent to find an answer, fast
In Foundations, it was selected for a Showcase variant and the Fracture Foil version of Doubling Season is the most expensive card of the set
Doubling Season has long had a little brother in Parallel Lives but until Amonkhet these effects were only in Green