For as long as Dungeons & Dragons has been around it seems like 4th level spells (especially for wizards) have been a wasted spell level. It seems like many 4th level spells could easily have been included with the 3rd level spells and nobody would think them better than the rest. Traditionally there were never many good damage-dealing spells at 4th level; this has been remedied with 4th and 5th editions though. Many 4th level spells that were invaluable in previous editions, like stoneskin and fire shield, have been severely lessened in their usefulness, or removed from the game altogether, like recitation and defensive harmony. There are also useful spells that have been moved from 4th level and placed in a higher spell level, like wall of ice.
This spell allows the caster to change one being into a new form; limited to humanoids and beasts. If the target is unwilling a wisdom saving throw is allowed to avoid the effects. The recipient keeps their alignment and personality, but mental and physical stats/abilities are those of the new form. When the spell’s duration of one hour ends, or if the target dies, then the target reverts back to their original form. When the polymorphed being reverts to their original form their hit points are restored to the pre-polymorphed total. A caster using this spell on themselves should have been given the opportunity to end the spell at any time as previous editions allowed, but this would have made the spell a bit too powerful for a 4th level spell.
9 Fire Shield
Before 3rd edition fire shield caused attackers to take an equal amount of damage they dealt to the caster (from normal melee attacks). In 5th edition this spell deals 2d8 points to an attacker who successfully hits the caster with a melee weapon or an unarmed attack.
This could potentially deal more damage than the caster received from the attack, but chances are it will deal less. Fire shield can also be cast to instead provide a chill shield – causing cold damage to attackers instead. Additionally, fire shield provides cold resistance, while the chill shield provides fire resistance. This spell is also useful in dark areas as it provides more light than a torch.
8 Freedom Of Movement
This is a great spell to cast before entering a dungeon, and its duration of one hour will likely last for a majority of the party’s time spent exploring the dungeon. This spell prevents any spell or natural hindrance from slowing the movement of the caster. Freedom of movement also prevents the caster from being paralyzed, restrained, or grappled. If caught in nonmagical restraints the caster need only sacrifice 5 feet of movement to break free. This spell would have been higher on this list had it been scalable; allowing it to affect multiple beings.
7 Greater Invisibility
This improved version of the 2nd level invisibility spell allows the recipient to perform actions that would have ended the 2nd level version. This means the recipient of greater invisibility is free to cast spells and attack opponents while remaining invisible until the end of the spell’s duration (which is one minute). This is deadly when used to make the party’s thief invisible – allowing the affected thief to perform sneak attacks every turn. Being invisible also grants the character an advantage in combat while giving attackers a disadvantage. This gives the invisible character two rolls of a d20 to try to hit her/his target (using the highest result of the two).
Recitation was a cleric/divine spell from earlier editions of D&D that did not make the cut into 5th edition. Recitation grants the caster and all beings friendly to the caster within 60’ a +2 bonus to their attacks. At the same time it inflicts a -2 attack penalty to all hostile beings within the 60’ radius area of effect.
This four point swing can make a difficult encounter much more manageable. Recitation does not require concentration once cast, has a duration of one turn per level of the caster, and works in conjunction with other buff spells like bless. This spell is detailed in Player’s Options: Spells and Magic and the Priest’s Spell Compendium.
5 Ice Storm
Ice Storm is another spell that has been given an upgrade for 5th edition. In earlier editions of D&D this spell did not allow a saving throw for half damage, but it also didn’t inflict that much damage either. In 5th edition this spell deals 2d8 bludgeoning, and 4d6 cold damage to everyone within the 20’ radius area of effect; a passed dexterity save reduces the damage by half though. In addition to the damage, ice storm also makes the ground within the area of effect become difficult terrain to navigate. The damage is scalable if the spell occupies a spell slot above 4th, but only the bludgeoning damage is increased (by 1d8 per spell level).
4 Dimension Door
Dimension door is the lowest level spell that allows for a (mostly) reliable teleportation effect. The caster opens a portal to another location within the spell’s range of 500’. The location does not have to be visible, but using this spell to teleport to an unseen location could result in the spell failing and the caster taking a fair amount of damage (4d6).
The spell's description does not expressly forbid using this portal to launch spells beyond their listed range; an example would be opening a dimension door 450’ foot away in the midst of a group of an opposing force and casting a fireball through the portal. The portal also allows one additional being, within 5’ at the time of casting, to also travel through it providing they are not encumbered.
3 Vitriolic Sphere
This spell causes a 20’ radius burst of acid to explode at a point of the caster’s choice within a range of 150’. The acid inflicts 10d4 points of damage to everyone caught in the area of effect, and an additional 5d4 at the end of their next turn. A passed dexterity save reduces the initial damage by half and negates the following 5d4 entirely. This spell is more useful than other offensive spells mainly because it is rare to encounter an opponent with resistance to acid damage. Vitriolic sphere is also scalable; adding a 2d4 to the initial damage for every spell slot it occupies above 4th.
2 Wall Of Fire
If a party is in trouble and needs to put a barrier between the enemy and themselves to facilitate a quick getaway, or for a moment to heal and regroup, there isn’t a better option at 3rd level than wall of fire. Using this spell the caster can create a barrier made of flame that is up to 60’ long, 20’ tall, and 1’ thick. Any creature that comes within 10’ of the outward facing side of the wall must make a dexterity saving throw or take 5d8 points of damage; a passed save halves the damage. This can also make a circular wall 20’ in diameter.
1 Evard’s Black Tentacles
Evard’s Black Tentacles (also sometimes called simply black tentacles) is one of the best damaging 4th level spells available. This spell causes black tentacles to sprout from the ground in a 20’ radius area. These tentacles attack all beings in the area of effect, or later enter the area - their attacks inflict 3d6 bludgeoning damage. A passed dexterity saving throw halves the damage, but a failed saving throw causes the victim to also become restrained by the tentacles. This spell has a large enough area of effect that an entire group of opponents will likely be affected. Restrained opponents cannot move and will be at a disadvantage; while those attacking them will have an advantage.