For a class as versatile as the artificer in Dungeons & Dragons, it can be hard to decide what you'll regularly rush into battle wielding. A good artificer ensures that they and their teammates are outfitted with the right tools for the job, battle or not. They do this with the fantastic benefit of Artificer Infusions, which allows them to craft several unique Magic Items and replicate several Magic Items found in the Dungeon Master's Guide.
A strong tactic for the class is utilizing their Infusions and unique spell list to bolster the other party members. At the same time, the artificer can devise a creative tactic to gain the upper hand surprisingly and smoothly. With this in mind, the weapons you'll bring should utilize only two at most of these Infusions so that the other slots can be put to more creative uses.
10 Cantrips
The artificer is primarily a spell-casting class and has access to several powerful, damage-dealing cantrips. Fire Bolt is among the finest, with a range of 120 feet and a d10 for damage.
This also frees up your Artificer Infusions to benefit the rest of your party. A group of adventures who have access to magic items, even common tier, at an early level is a rare occasion. It can improve the quality of life for your friends and your group's chances of survival.
9 Imbued Wood Focus
An Imbued Wood Focus has eight variations, each resonating with the energy of a different plane, which you can flavor to your campaign's liking. Each version of the Wood Focus has a specific damage type related to it, which allows you a +1 bonus to a spell with a matching damage type. The best weapon variant for the Focus is a staff, which can also deal melee damage.
This is a common wondrous item, so it's not off the table for a Dungeon Master to award this early on. In the hands of an Alchemist artificer, this can scale reasonably well with the Alchemical Savant ability.
8 Sling
Often overlooked, the sling is a simple ranged weapon that lobs 'bullets' (tiny stone pebbles) at targets up to 30 feet away (or up to 120 feet with disadvantage). It only deals a d4 of damage, but there's a way to fix that, and it won't cost you one of your precious Infusion slots, so you can save those for something else.
You'll want the Magic Stone cantrip, available to artificers, which you can use to imbue your sling ammunition, causing it to now deal a d6 plus your spellcasting modifier. This cantrip only takes a Bonus Action to cast, so it gels nicely into your action economy.
7 Shortbow
The shortbow is the way to stay the furthest from danger. It only deals a d6 of damage, but for the range and its property as a simple weapon, it's worth a mention.
The Enhanced Weapon infusion will automatically give the shortbow a +1 bonus to both the attack and damage roll. This also grants the shortbow the benefits of magic damage. At later levels, you'll even be able to replicate Bracers of Archery, giving you an extra +2 to an arrows damage roll.
6 Hand Crossbow / Thrown Weapon
For this setup, the War Caster Feat is recommended so that having both your hands occupied doesn't inhibit your ability to cast spells. You'll also need to be able to use martial weapons, but some races grant that already. Plenty of light, simple weapons have the thrown property, but some favorites are the Hand Axe, which deals a d6 but requires strength, or the dagger, which has the Finesse property (can use Dexterity to throw it) but only deals a d4.
Hand crossbows have properties like Loading and Ammunition that you'll get to ignore with the Repeating Shot Infusion. Then infuse your thrown weapon with Returning Weapon, which immediately brings it back to your hand after using it to make a ranged attack. Since both are Light, your Action and Bonus Action can be spent flinging axes, daggers, and bolts from a safe spot, all with a +1 to attack and damage rolls.
5 One-Handed Weapon / Shield
At level six, an artificer has a couple of Infusions that will boost the benefit of having a shield, which is already very useful if your character suffers from a low Armor Class. Again, you'll need the War Caster feat, allowing you to ignore the somatic component of any spell. Still, it's a great feat in general for specific subclasses of the artificer for its other benefits.
Sticking to simple weapons, the mace is a great way to deal out a d6 of damage. You can infuse this with Enhanced Weapon if you like, or even infuse it with Radiant Weapon for an extra chance of blinding a target as a Reaction. You'll then want to infuse the shield with Repulsion Shield, which gives you a new Reaction to push attackers backward fifteen feet and gives your shield an additional +1 to your Armor Class. Are you a paladin? A cleric? Nope, just a zany, magical inventor.
4 Wand of the War Mage
If you're not looking to get your hands dirty, then the Wand of the War Mage is an excellent choice. This simple but effective magic item ranges in rarity based on how much of a bonus it offers to your spell attack and damage rolls and allows you to ignore half-cover against a target.
Considering that you have a hand free, it's still best to fill your off-hand with a Light simple weapon with the Thrown property or a shield. This way, you can benefit from one of the Infusions that will either maximize your damage potential on your turn or keep you extra protected from unexpected attackers.
3 Homunculus
At second level, an artificer who prefers a more versatile loadout can choose to use one of their Infusions to create a Homunculus. This tiny mechanical creature acts as your companion in and out of battle. The biggest downside is how pricey it can be to create, costing you a gem worth 100 gold. However, you can bypass this early on when creating a character by choosing gold instead of starting equipment. You'll most likely have enough gold left over to get a weapon of some sort too.
The creature has a stat block that grows in power alongside your artificer. Alongside that, it's armed with Evasion, proficiency in Stealth and Perception, darkvision, a ranged attack, and the ability to channel your Touch spells through itself (keeping you out of danger.) And if your new buddy comes into a tight spot, you can heal them with the Mending cantrip.
2 Arcane Propulsion Armor
This is by far not the 'best' weapon in terms of damage output or Infusion versatility, but it is the coolest. You can either acquire the Arcane Propulsion Arm, which requires attunement (and a missing limb), or wait until you're level fourteen and infuse your own armor.
With either of these options, one or both of your arms becomes a cannon that deals a d8 of Force damage and has the Thrown property, allowing you to hit a target up to 60 feet away. With all that said, if you walk the artificer path of an Armorer, this Infusion is the beginning of your journey to becoming a medieval "Iron Man."
1 All-Purpose Tool
Essentially a Sonic Screwdriver from Doctor Who, the All-Purpose Tool is a magic item only usable by artificers and is one of the best weapons for the class. Like the Wand of the War Mage, it comes in three different rarities.
Depending on your variant, this offers up to a +3 to your attack roll and your spell save DC for your artificer spells. It can also serve as every type of Artisan Tool, granting you immediate proficiency with that Tool and a Cantrip from any class list every eight hours. The artificer class is uniquely powerful in that it has an answer to a variety of problems, and the All-Purpose Tool only highlights and aids the wielder with that same quality.