As a long time Wizard player who has also played a Sorcerer, one thing I've noticed is that people seem to forget the Wizard's flexibility in spell selections and often times stick to a single spell set selection and tend to just get by based on this. I think part of this is simply a misunderstanding of the spells themselves. Now don't get me wrong not all spells are good all the time and some spells are niche. But as a Wizard one can afford niche when niche is needed

Grease
When most think of grease the first thing out of their mind is griefing a party. But the purpose of this spell is two fold.
1. Slow down groups of melee mobs
2. When combined with a fire source becomes a cheap lesser wall of fire
Places where this excels is in slopped dungeon areas, or narrow passages and doorways where if the first mob through is slowed it slows the ones behind it.

Obscuring Mist / Fog Cloud
This gives all creatures a 20% concealment that are inside the mist. This spell is often used on the mobs where it would be better used on the party while they range mobs. Melee fighting on the edge so as to enjoy the 20% miss chance without granting it to the mobs.

Sleep / Deep Slumber
This spell is commonly overlooked. This has more to do with the everything must die approach to completing a dungeon. However, quests that have criteria that you don’t want to kill certain mobs this spell works as an approach to keeping them out of the fight. When applied strategically this can allow you to pull mobs such as Ogres away from Wildmen miners.
These spells can also help in dungeons where you don’t need to kill a group of mobs, just need to get past them. As it helps those with or without stealth abilities.
Sleeps DCs are a bit different so depending on what you are using it on your Saves could be higher or lower than your usual Enchantment Spells – Spell’s DC minus the HD of the Target plus your Caster Level. Deep slumber does not have the same HD adjustment.
Now in a 2nd Level Quest a caster will commonly be CL4 (Many run Elite quests 2 above base). Considering a 20 caster attribute average (Newer players less, older a bit more) the DC of this spell (without heighten) will be 10 Base + 1 Spell Level + 5 Caster Bonus + 4 Caster Level = 20 minus the HD (As long as the HD are less than your caster level you will get a bonus above your Enchantment spells)

Now just a few cases in point –
The Cannith Crystal – Here as a caster you can get overwhelmed quickly towards the middle when you get multiples of 2 and 3 spawn at the same time. Use of Sleep will stop them in their tracks and allow you to then handle them one at a time.
Stealthy Repossession – I know a lot of people that hate running this quest and many that run this don’t use stealth but instead run from lever to lever trying to stay 1 step in front of Red Alert. However, if you took the approach to sprinkle Sleep (which also comes as a clickie on SDK end reward “Bottle of Sleep”) you can avoid the prophets and kill the shaman/regular kobolds without raising alert. And a sleeping kobold doesn’t attack so it won’t die to guard damage. It can also make a quest that people commonly solo much more fun in a group.
Let Sleeping Dust Lie - Deep Slumber on the Spiders. The spiders can get very jumpy and move in the way, I’ve found that Deep Slumber works well on these as it stops them in their tracks (I think this is because they are classified as Magical Beasts and not Vermin)

Cause Fear / Scare / Fear
At one point this followed the HD criteria but since then it can be a good utility spell at any level. Cause Fear being single target it has some uses when you only want to get one target.
Frightened effect –
Mob flees from you and -2 Attack/Saves/Skill/Ability checks. You just gained +2 AC and +2 DC vs the mob.
Shaken effect (on save) -
-2 Attack/Saves/Skill/Ability checks. You just gained +2 AC and +2 DC vs the mob.
Save or not you just made your next spell easier to land and you have taken some bite out of the mob. This is best used on low will save mobs. However, I have also found it useful in slowing down archers by targeting the one groups are not fighting.
Now I can understand there are people that don’t like fear type effects because the mob runs away from you. This can be bad in a couple cases. Such as all the melee are trying to chase the mob running away, or mob runs into a room agroing everything in that room too. So be careful when you apply fear as you can get more then you bargained for.

Chill Touch
Now this spell does not do a whole lot of damage, but it does drain a point of strength on living creatures. But I have found its best use is with Undead. The Fear effect it has on undead can save you when you get boxed in. Applying it to undead Archers stops them dead in their tracks. Do be careful using this as I’ve had to wait 5 minutes in Free Delera (Delera’s Tomb) because I applied chill touch to a Soul-Lock Guardian and they ran off through the barrier where we could not follow.
I have found this spell to be useful in quests like From Beyond the Grave where you need the undead to leave you alone while you light the pyres. Feared Skeletons don’t have the respawn rate of dead ones.
I do remember a long time ago in From Beyond the Grave I used Chill Touch on Deathshade and caused him to be feared – I don’t think that works anymore but my friend and guild mates had a huge laugh and dubbed me the one that even Death fears (Hehehehe)

False Life
Ok it is only up to 20 Temporary HP. But keep in mind it is a minimum of 11 Temporary HP which is still more HP then you have. Combined with other damage mitigation effects and the fact that this comes on a wand and stacks with abilities like Aid and Greater Heroism’s temporary HP effects when used in conjunction you can have a minor “Shining Through” something you need to recast before you engage. However, I’ve found that combining these types of effects is also a great way to survive a trap you need to run through, or even a gauntlet of Archers.

While wands and scrolls are not quick ways to apply this, they are cheap. 11 to 20 Temporary HP can help keep you up in situations where you have to take a few shots and your current HP pool is a bit low.

Ghoul Touch
While only useful on humanoid creatures, this is a single target hold spell. Very useful in pinning down a mob prior to releasing a volley of MM or pulling out a melee weapon, or simply setting a mob up for the party. One of my favorite tactics with this spell in content full of humanoids is to weave in and out of mobs paralyzing at will leaving a trail for the rest of the party to simply hack apart. Now obviously Mass Holds and Hold spells can be done from further away, but this particular spell it is based on Fortitude and Necromancy DC vs Will and Enchantment. This spell was very useful during my Arcane Melee phase.

Ooze Puppet
Charms an ooze similar to charm person. Useful in reducing the number of ooze you need to fight at any given time. Additionally, Living Spells found in the Sub terrain and in Revear’s refuge are also affected by this spell.

Slow
You would have thought that the reverse of Haste would have caught on as a popular spell. While Haste improves a group by 32% run speed and 15% attack speed, slow reduces run speed by 50% and attack speed by 30%. This spell also reduces AC, Attack and Reflex Saves by 1.
Places where this spell shines is verse large groups of mobs that swarm the party such as Breaking the Ranks, or slowing down attacks by archers that are out of melee reach, or in places like Lines of Supply where supply carriers are trying to run away from you.

Lesser Globe of Invulnerability / Globe of Invulnerability
These spells do stay in one place, but when fighting against casters these spells are worth their weight. Lesser Blocking up to 3rd Level and the other blocking up to 4th Level spells. Now if a spell is based on a lower level spell such as Mass Deathward it can be blocked since its single target version is a 4th level spell. Why is this important? Have you ever faced a mob that gets deathward cast on it? By casting a Globe of Invulnerability over it instant death effects can now be used. It is like having your own minor Anti magic field you can cast and remove buffs. Additionally, it can save you from being spammed stun spells. Now this spell lasts 30 seconds and can be extended. This means that a scroll will last as long as a non-extended version of this spell. This is useful as you can carry a few scrolls with you for utility and still not worry about using SP for something you are done with but it still has time on it.

Also known is how standing in a Globe also stops the effect of Bees from the Hound of Xoriat.

Feeblemind
Reduces Intelligence and Charisma to 1. While it should basically kill an arcane casters ability to cast spells, I cannot vouch that that is what happens as most of the time by the time I’ve hit one with this spell they don’t usually get more time to react as so many players target spell casters for obvious reasons. However, this spell also works well in conjunction with an Attribute damage effect be it spell or weapon effect. I’ve actually seen more Intelligence Damage effects with the new Random Loot system.

Mind Fog
Now there was a discussion awhile back where it was confirmed by development that Mind Fog only reduces the will save by -10 if they fail their will save. And I know some of you are think, well how can that be helpful if they have to fail a will save in order for me to get an advantage on will save.
If you think about it in terms of resources, there are actually a few things that can come to mind.
First, DC burst effects. There are a few abilities be they Heroic enhancement trees, or epic core abilities and even some gear that allow a temporary boost be it 6 to 20 seconds. Mind Fog last a while like most cloud based spells. Using these boosts on this type of ability means its higher DC has now made it more likely for your non-temporary boosted spells to land.
This then potentially makes it possible that you will be able to land these will saves without the need for Heighten. I know someone is going to spit their coffee at their screen at that idea, but consider that Heighten at the most adds 8 to your DC (For First Level spells) so consider how much you are spending when you still have a DC advantage. Now mind you in Legendary Elite turning off Heighten probably won’t be a good idea, but you can use those boosts on stuff that will give you more bang for the SP buck and giving you a longer chance then say negative levels at Epic.

Ray of Enfeeblement / Waves of Fatigue / Waves of Exhaustion
These don’t have a save, they do have spell penetration checks. I have found these to be very useful vs brutes most of which don’t have spell resistance. That ogre that can clean your clock with his double hit to reducing the melee power of Champions, Orange and Red Named (Seems to be bugged on purple as it should work but it doesn’t.)

Ray of Exhaustion
While these have a save, the save still applies fatigue which is a -2 debuff to Str and Dex which is a +1 to Reflex DCs as +1 AC vs that affected creature.

These spells can help out even for a non-DC focused characters as Exhaustion slows the mob down. The slower it goes the less damage it does.

Now some of these spells work even at epic levels. Enfeeblement/Waves of Fatigue/Exhaustion based on my findings are not part of the Epic Recovery. While I’ve found some Red named as well as all the Purple named appear to be immune, they are still effective against dangerous creatures. The Ray spells are good against beholders since their attributes are generally very low and slowing down their attack rate makes it safer to get closer.


Symbol Spells.
These are hard to use, but I find they are best in arena type content. This is largely because people don't pull into kill zones as a common practice during normal quest runs. Symbols have a lasting effect even after they are triggered, but you need to kite them in and out of the area of effect during that time. Symbol of Persuasion is a good way to reduce incoming damage and get mobs to fight each other, Weakness is a good way to also reduce incoming damage. Pain is good as it acts like a mass curse when used strategically.