I was thinking shield save you form a strike, but what about a spell that saves you from a crit?

Strike Break

1st-level abjuration

Casting Time: 1 reaction
Range: 30 feet
Components: V, S
Duration: instantaneous

An field of magic force stops a strike from decimating a target, but merely causes the target to be pummeled.  When you cast this spell, a target in range is no longer subject to a critical hit, but is struck as normal with an attack or spell.  This will only affect one strike even if the target is struck with multiple critical hits in a round.

Thoughts?

Let’s keep up with the against the giants push with another spell-Gravity Crush

Gravity Crush

3rd-level evocation

Casting Time: 1 action
Range: 150 feet
Components: V, S, M (a ball of lead)
Duration: Instantaneous

You cause the ground to instantly quintuple the gravity of a point in range.  Each creature in a 20-foot-radius of the point must make a Strength saving throw. A target takes 5d6 magic bludgeoning damage on a failed save and is knocked prone, or half as much damage and avoid being knocked prone on a successful one.  Creatures that are large or larger make this save with disadvantage.

At Higher Levels: When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.

Let’s keep building on the theme of big enemies taking bigger damage!

Power Throw

1st-level evocation

Casting Time: 1 action
Range: 30 feet
Components: V, S, M (powdered rock)
Duration: Instantaneous

You cause a large force to throw two targets into one another.  Choose two targets within range to make separate Strength saving throws.  On a failure, the target is throw up to the range of the spell.  If the target is throw into another target that also failed a saving throw, the recipient and and the target take magical bludgeoning damage as shown below based on their respective sizes.  As an example, if a large creature is thrown into a medium creature, both creatures take 2d6+2d8 magic bludgeoning damage.  The thrown creatures ends prone.  If no two targets fail their saving throws, then any who did may be moved up to the spell’s range and take damage as below as they are thrown to the ground.

At Higher Levels: When you cast this spell using a spell slot of 2rd level or higher, increase the number of targets of the spell by 1 for each slot level above 2nd.

Let’s get some more DnD 5e to the table shall we?  It’s time for a spell..

Fast Healing

2nd-level evocation

Casting Time: 1 action
Range: Touch
Components: V,S
Duration: Concentration, up to 1 minute

You conjure the healing power of the universe and cause the target of the spell to regain hit points equal to your spellcasting ability modifier at the start of its turn.  You or the target may move after you cast this spell, but must remain within 50 feet of each other or the spell ends on that target. This spell has no effect on the dead, undead, or constructs.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, you may target another creature for each slot level above 2nd.

Thoughts?

Let’s build off some ideas I’ve seen.  I want a magic taser.  We can do that with a spell!

Neurological Shock

1st-level evocation

Casting Time: 1 action
Range: 50 feet
Components: V, S
Duration: Instantaneous

You throw a ball of electricity at a target temporarily stopping the the target from being able to think, much less move.  The target must make a  a Constitution saving throw. On a failed save, the target takes 2d8 lightning damage and is stunned until the end of your next turn. On a successful save, the creature takes half as much damage and is not stunned.

At Higher Levels: When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d8 for each slot level above 1st.

Let’s get back to our roots with a cantrip for DnD 5e

Sound Ball

Evocation cantrip

Casting Time: 1 action
Range: 50 feet
Components: V, S
Duration: Instantaneous

You hurl a ball of pure sound at an opponent. Make a ranged spell attack spell attack against the target.  On a hit, the target takes 1d6 thunder damage and is pushed 10 feet.

The spell’s damage increases by 1d6 and the pushed distance increases by 5 feet when you reach 5th level (2d6 and 15 feet), 11th level (3d6 and 20 feet), and 17th level (4d6 and 25 feet).

Thoughts?