I just bought a book from the DM's guild and I found this cantrip in it, I both love it and feel like it might be a bit much. Whats everyones thoughts?

Getting a choice of damage type is rather powerful as you can basically get passed any damage resistance/immunity. 

Personally I would not allow that as DM. Not from a cantrip. 

A bit strong, but would perfectly fine as 1d6 damage.

So they just took Chromatic Orb and made a cantrip out of it, with the addition of poison damage choice? And no costly material component?

Yeah... I think it's a bit much for a cantrip. Mainly because it's too versatile, especially with the choice of poison.

Like, I made a cantrip based on Chaos Bolt for our Wild Magic Sorcerer to use (Chaos Shot), but it's got randomness to it, with the concept of gaining more control and power by having more damage types to choose from as you add dice at the usual character levels.

Edit: I've been informed/reminded that Chromatic Orb also has poison damage as a choice. My bad.

That kinda how I felt. I thought if I allow it I’d reduce the damage to a d6 OR allow the damage to be selected only after a long rest not at will. 

You could just reduce the damage to d6 as Zenlos2_0 suggested, and then use that to determine the damage type randomly each casting:

1. Acid
2. Cold
3. Fire
4. Lightning
5. Poison
6. Thunder

You would just have to specify that the very first damage die is the one used to determine damage type to avoid contention at levels 5+ (if you catch my meanin’). The display on DDB’s roller lists the individual rolls when tallying damage, so even if you’re players are using that it will be available automatically so they won’t have to remember to roll anything else, and that should stay available in the game log if they forget to pay attention. (And you’ll be able to double check if they seem to conveniently get beneficial damage types more of them that you think statistically probable.)

 To be fair, I have never ever felt the versatility of Chromatic Orb being a critical factor for its usefulness and thus I think this cantrip is perfectly fine, I would allow it at my table if I would allow homebrew in general.

I don't even understand why Chromatic Orb needs a costly component except that a gem as its component fits its flavor, it is not even a good spell. It might have been a good spell, if the various damage types actually had side effects baked into them that made the choice relevant even outside of going around elemental resistances (which are quite rare at lower levels), but as is, it is an okay-ish damage spell that could easly have dealt psychic, necrotic, radiant or force damage without being able to switch type and would be just as good, if not better because you aren't wasting it if you are not aware of a monster resisting a particular elemental damage type.

1d8 with being able to switch damage types as a cantrip is perfectly fine, and considering adding poison damage adds nothing in terms of power to the spell (as there is no monster that resists all elemental damage but poison and dealing poison damage does not automatically cause the target to be poisoned) I don't think it having that over Chromatic Orb is a reason to nerf its damage. However, removing poison damage would be perfectly fine too to keep it in line with Chromatic Orb and other spells like Absorb Elements and Primordial Ward that all are related to the five elemental damage types.

Indeed, if you would go with Toll the Dead, you would deal a d12 damage at the same 60ft range and, unless you face powerful undead, you would not have any issue with damage resistances, and if you take Chill Touch, you have an attack roll cantrip with 120 ft range that deals a d8 necrotic damage and has an useful sideeffect in preventing any healing.

I Disagree.

Careful diversification of combat Cantrips to provide the PC an attack option against lower AC foes, and at least one forced save cantrip for the others, with a variety of damage types to get around resistances and immunities is part of why cantrips is the most highly competitive level of spells for those scant few each PC gets to learn. One attack roll cantrip and two forced save cantrips with a variety of damage types eats 60%-75% of most PC’s total cantrips, and 50% for Sorcerers. It’s a strategic exercise to limit one’s choices of “useful the rest of the time” cantrips (or find ways to squeeze them in). One of my go-to attack cantrips I’d chill touch, and one of my go-to forced save cantrips is toll the dead, but never on the same character. Especially if I decide to sacrifice the security of having options and limit myself to two combat cantrips to make rom for something I value more (like all of the non-combat cantrips).

In addition, cantrips are supposed to be super-simple spells, having an active selection of damage types from a list of half a dozen potential choices is not cantrip level “super-simple spellcraft.”

If you think resistances must be rare at low levels... our level-2 party encountered Ochre Jellies. Resistant to acid, immune to slashing and lightning damage, and they split in 2 if you hit them with slashing or lightning damage. That was a fun battle, if less fun for our barbarian wielding a greataxe, and my gnome artificer was chagrined to find her new Lightning Lure wasn't as helpful as she'd hoped. (Our wild magic sorcerer was relieved that she hadn't picked lightning damage when she rolled it on a casting of Chaos Bolt...)

I know these monsters, I have fought them myself... but what I wanted to say with my post and why I believe the cantrip is fine as written with the ability to choose between the different elemental damage types, is, if you like lightning damage, you will probably still use a lightning-typed Chromatic Bolt at them when you attack them for the first time, wasting your turn - because you don't know that they are immune to lightnig damage. And on your next turn, you then could use a different damage type of Chaos Bolt - or a different cantrip like Fire Bolt, Toll the Dead, Ray of Frost, Mind Sliver... that deals more damage (especially when Chaos Bolt is nerfed to a d6 like some suggested) and/or has a useful side effect or considerably more range.

While being able to choose damage types increases versatility, it does not help you to avoid resistances you don't know - using a very rarely resisted type like psychic, radiant, necrotic... would do that on the other hand in most scenarios. In addition, a d6 damage is so low that a resisted tier 2 Tire Bolt for 2d10 damage halved (5.5) only deals 1.5 less damage on average than a neutral Chaos Bolt for 2d6 (7) damage.

What I agree about though is that @IamSposta said cantrips are supposed to be very simple, which a cantrip that allows choosing damage types is not really. Making the damage type random could be an interesting idea though, then it basicially would be a cantrip version of Chaos Bolt and a thematically great pick for wild magic sorcerers.

I'm in the "reduce damage to 1d6" camp. Yes, you get to bypass resistance. You also get to bypass resistance in 95% of cases with Mind Sliver, and it has an extra effect to boot. Same goes for Sacred Flame, but bump it to 98%. And then there's Sword Burst.

In effect, this kind of cantrip is not that different from a psychic, radiant, or force cantrip with the additional rider being that you can occasionally exploit a vulnerability. But at the same time it has a very different flavor that I could happily build a whole character concept around.

The absolute least residented/immune damage type is “B, P, & S from magical attacks/weapons/sources.” Force is #2, then Radiant @ #3, Psychic @ #4, followed by Necrotic @ #5. Technically, a moon-touched sword is better than eldritch blast in regards to bypassing resistance/immunity.

Quote from IamSposta >>

The absolute least residented/immune damage type is “B, P, & S from magical attacks/weapons/sources.” Force is #2, then Radiant @ #3, Psychic @ #4, followed by Necrotic @ #5. Technically, a moon-touched sword is better than eldritch blast in regards to bypassing resistance/immunity.

 Which means Magic Stone is the best cantrip. (Except against swarms.) ;)

Quote from Jessebruffett >>

I just bought a book from the DM's guild and I found this cantrip in it, I both love it and feel like it might be a bit much. Whats everyones thoughts?

 ChromatIc bolt

Evocation cantrip

Casting Time: 1 action
Range: 60 feet
Components: V, S
Duration: Instantaneous
Classes: Artificer, Sorcerer, Wizard

You hurl a mote of elemental energy at a creature or object within range. You choose acid, cold, fire, lightning, poison, or thunder for the type of bolt you create, and then make a ranged spell attack against the target. If the attack hits, the creature takes 1d8 damage of the type you chose.

This spell’s damage increases by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).

 What book was it?

Fizbans Vault of Draconic Secrets