On paper, neither of these cards sound particularly overpowered
Obviously, this card is an incredible Lessons payoff, and any Iroh, Grand Lotus deck centered around the card type will want this Chakra Meditation in the 99
There are others who revel in pointless calamity (Blim, Comedic Genuis), savage bedlam (Etali, Primal Storm), or even pure profit (Starke of Rath)
Prismatic Endings are a nice versatile answer to both graveyard hate cards and small cost creatures, like Deaths Shadow or Monastery Swiftspear
They all happen to be Red, which certainly fits into the Gruul color combination, but they just didn't feel like Gruul cards to me
Myrel, Shield of Argive's first ability prevents opponents from activating abilities of permanents on the battlefield that are artifacts, creatures, and/or enchantments