Cantrip Connoisseur

Cantrips are considered to be the easiest, most utilitarian, and often the least impressive form of spells in the world. They take almost no effort to cast and can be used endlessly unlike more potent spells, but most practitioners of the various arts of spellcasting give them only a cursory study after having used them as a stepping stone to the deeper reaches of their magical potential. However, you are not the typical spellcaster.

Forgoing the intensive study of powerful spells which carry their own potent effects, you have chosen to delve headlong into the use of the most basic magical arts to accomplish far more than would ever be expected on them. The breadth and depth of your knowledge of cantrips is staggering. Some consider it pointless to dwell on and dedicate such time to the basics, but you know that it is the basics of any craft which hold the most fundamental secrets.

 

Expanded Tome

At 2nd level, you have learned the trick to keeping a greatly increased number of basic spells on hand at all times. You can learn an additional three cantrips from the wizard spell list. They do not count against the number of cantrips you know.

Arcane Dabbling

Starting at 2nd level, the cantrips you may learn increases to include those of sorcerers and warlocks as your studies allow you to tap into and memorize their arcane methods. You may learn one cantrip from each of these two classes' spell lists and not count them against the number of cantrips you know. Sorcerer and warlock cantrips count as wizard cantrips for you and use your Intelligence instead of Charisma.

Natural and Divine Magics

Starting at 6th level, the cantrips you may learn increases to include those of clerics and druids as you have found a way to just barely meld the rigorous academic studies of a wizard with the more faith based methods of druids and clerics. You may learn one cantrip from each of these two classes' spell lists and not count them against the number of cantrips you know. Cleric and Druid cantrips count as wizard cantrips for you and use your Intelligence instead of Wisdom.

In addition to this, you can cast non damaging cantrips as bonus actions.

Enhanced Cantrips

Your incredible focus on mastering cantrips grants them extra potency. Damaging cantrips add your spellcasting modifier to the damage roll and non damaging cantrips that do not require concentration can have an additional number of castings active at the same time equal to your proficiency bonus.

Ex: If your proficiency bonus is +3, you could have up to 4 effects of the Light cantrip active at the same time. (The original casting then three more afterwards.)

(Note: I cannot find a way to make this feature work as intended in D&D Beyond.)

The Science of Song

Beginning at 10th level, the cantrips you may learn increases to include those of bards as your analytical mind has memorized the rhythm and wiles of that which stirs the heart. You may learn two cantrips from the bard spell list and not count them against the number of cantrips you know. Bard cantrips count as wizard cantrips for you and use your Intelligence instead of Charisma.

In addition to this, you may cast damaging cantrips as a bonus action or attack of opportunity a number of times equal to your Intelligence modifier between short rests. If you have the War Caster feat, you may cast any cantrip as a reaction when you can make an attack of opportunity.

Ascendent Cantrips

At 14th level, you are able to tap into the base essence of all of the cantrips that you have mastered, granting you a power over them that ascends them to the level of more complicated spells. By expending spells slots, you are able to magnify the effects of a cantrip in a number of ways:

• A damaging cantrip can be granted advantage on its attack roll or impose a disadvantage on the saving throw against it by expending a 1st level spell slot or higher.
• A non damaging cantrip's duration can be doubled by expending a 1st level spell slot. Expending a 2nd level spell slot triples the duration to a maximum of thirty minutes. Expending a 3rd level spell slot can extend the duration up to one hour. Expending a spell slot higher than 3rd level adds an additional hour per level above 3rd. You can dispel an extended cantrip at any time with a bonus action or reaction.
• The damage inflicted by a cantrip can bypass resistance to its damage type by expending a 1st level spell slot or higher. Stacking this effect with itself by expending two different spell slots allows the cantrip to bypass immunity to its damage type.
• You can sacrifice any number of spell slots of any level to add the cumulative level of all sacrificed spell slots to the attack roll and damage rolls of the cantrip. If the cantrip instead causes the target to make a saving throw, you may add that total to your spell DC. For example, by sacrificing a level 1 spell slot and a level 2 spell slot you would gain a +3 to your attack roll and each damage roll.
• By expending a 2nd, 4th, 6th, or 8th level spell slot, you can cast the cantrip an additional time with the same action for every two levels of the slot used. As such, a 2nd level spell slot allows you to cast the cantrip two times at once and an 8th level spell slot allows you to cast the cantrip five times at once. Each extra casting of the cantrip can target a different object, space, or creature or all of them can target the same one. Combining multiple castings of cantrips such as Light or Mage Hand may have compounding effects as per your DM's discretion.

These effects can be stacked by expanding multiple spell slots.