True Strike

You extend your hand and point a finger at a target in range. Your magic grants you a brief insight into the target’s defenses. On your next turn you gain advantage on your first attack roll against the target provided that this spell hasn’t ended.

Literally the only way to make the worst spell worse

“That guy 👉 is holding a shield”

Power Word Kill

You utter a word of power that can compel one creature you can see within range to die instantly.

No more 100 hp limit. Instant death for anyone.

Creation:

You pull wisps of shadow material from the Shadowfell to create a nonliving object of vegetable matter within range: soft goods, rope, wood, or something similar. You can also use this spell to create mineral objects such as stone, crystal, or metal. The object created must be no larger than a 5-foot cube, and the object must be of a form and material that you have seen before.

“How far away is the BBEG’s fortress?”

“His lair is still many leagues in the distance. You can just barely see it on the horizon, nestled in the-”

“I spawn a really big boulder on top of it. Like, a reeeally big boulder.”

“…”

Removing the radius definition from literally any spell

Hold person: At the end of each of its turns, the target can make another Wisdom saving throw

Remove the risk of losing the ability to cast Wish.

Remove the limitation on what you can do with the second action from Haste.

A lot of spells only have one sentence about resisting or avoiding the effect. Like remove the save from Polymorph on an unwilling target, or remove the ability to discern most illusion spells.

My favorite magic item I ever got was Ring of the Grammarian. Change one letter of a spell…

Me: “Incestation” Dm: “hello, step brother.”

Control Flames

You choose nonmagical flame that you can see within range and that fits within a 5-foot cube. You affect it in one of the following ways:

You instantaneously extinguish the flames within the cube

I turn off the sun