From powerful creatures to game-changing spells, the possibilities are nearly endless
Not only does this mean the number of times you can activate the abilities are limited (by my count, Esper Dragons, the tier one deck that runs the most spells in standard, plays 25 instants/sorceries), but also that Disciple of the Ring is directly competing for the same resource as extremely powerful delve cards like Tasigur, the Golden Fang and Dig Through Time and also a nonbo with the new spell mastery mechanic
You can blink your entire board with cards like Glimmerpoint Stag, or give +2/+0 to everybody using Battle-Rattle Shaman
Ok the bit youre interested in the actual cards that make up the deck
Roshan, Hidden Magister does the same, alongside granting some evasion, which goes well with Glitch Interpreter
If multiple sources deal damage to a creature with an enrage ability at the same time, most likely because multiple creatures blocked that creature, the enrage ability triggers only once