I have been offered an uncommon magic item of mostly my choice (The DM may decide it is too powerful and ask me to select something else but said most uncommon should be OK) and I am wondering what would be best.

It is for a level 6 Human Samurai fighter with Archery fighting style. Ability scores are Str=8, Dex=19,  Con=16, Int=10, Wis=13, Cha=10. Feats of sharpshooter and resiliant dex.

The character is used on a discord server with several "campaigns" though each session is run as a one-shot with different party members, having said that there is often a lack of melee  characters. I am involved in 2 campaigns, one is a dungeon crawl and the other mostly takes place in an urban environment.

I have 4 ideas but I am not aware of many of the magic items outside basic rules so any other ideas are welcome:

1. Cloak of protection, one strength on my character is survivability (proficiency in all 3 major saves by level 7) so this would enhance that  
2. Goggles of the Night, mainly of use during the dungeon crawl but the urban setting is also sometimes at night, sometimes I am the only character without dark-vision so be would not to have to show our presence if I had these.
3. Gauntlets of Ogre Power, allows me to be effective in things like grappling if I get into melee as well as taking the brute force approach to locked doors etc. 
4. +1 Long Bow most of the time I use a longbow so this is the obvious option.

Of those, I would probably go with the goggles, but would also consider winged boots or bracers of archery.

I am incapable of not saying Alchemy Jug, it is by far my favorite magic item, and it is uncommon. It is SO much fun to use and play around with. I mean, you can use oil to light stuff, get poison or acid for combat, drink some alcohol, or put out fires.

And the biggest point is, do you know a single magic item that can make 2 whole gallons of mayonnaise.

Offensively, Bracers of Archery is nice, however bear in mind many mobs at this tier will start to become resistant/immune to non magical damage, so the +1 Longbow edges ahead. Defensively, I like Stone of Good Luck (Luckstone), as it also wraps in utility. Finally, may I throw in a Longbow of Warning - this has nice utility and ticks the box vs non-magical resistant/immune mobs.

Aside:
> And the biggest point is, do you know a single magic item that can make 2 whole gallons of mayonnaise.

Using this item for this purpose automatically changes your alignment to Chaotic Evil.

Quote from BobobSyxtieNein >>

I am incapable of not saying Alchemy Jug, it is by far my favorite magic item, and it is uncommon. It is SO much fun to use and play around with. I mean, you can use oil to light stuff, get poison or acid for combat, drink some alcohol, or put out fires.

And the biggest point is, do you know a single magic item that can make 2 whole gallons of mayonnaise.

 Why would you not link to the alchemy jug on DDB?

Quote from DxJxC >>

Quote from BobobSyxtieNein >>

I am incapable of not saying Alchemy Jug, it is by far my favorite magic item, and it is uncommon. It is SO much fun to use and play around with. I mean, you can use oil to light stuff, get poison or acid for combat, drink some alcohol, or put out fires.

And the biggest point is, do you know a single magic item that can make 2 whole gallons of mayonnaise.

 Why would you not link to the alchemy jug on DDB?

 Sorry, that's the link that I use, because I don't have any of the books bought on DND Beyond.

Bracers of Archery as others have noted.

Gloves of Missile Snaring, Hat of Disguise for the Urban game or of course, the good old Stone of Good Luck(Luckstone). [Edit: Luckstone is a pain to magicitem tag.]

+1 long bow you can never go wrong with this.

Goggles of nightvision is also very usefull

While i like the Gauntlets of Ogre power, i hardly see how it would be relevant in your build and play style...

Its nice to have a +4 on STR ability checks and saves, but thats about it in your case...

I'd recommend Bag of Tricks nothing wrong with generating your own tank so you can focus on putting holes in the bad guys.

Bag of Holding?

Okay but, consider: Decanter of Endless Water.

I may or may not like to be creative and tricksy with my items.

Two words- immovable rod

Infinite uses

I would get a Perriapt of Wound Closure

It's kind of boring, but I'm also going to say +1 Long Bow. Bracers of archery are a bit more exciting, but as Buxton mentioned, you're going to start running into monsters that are resistant to attacks from non-magical weapons. Bracers of Archery give you a better boost to damage, but the weapon is still not considered magical for the purpose of punching through resistances.

He's also got Sharpshooter. Every bonus you can get to attack is very useful when you can pay -5atk for +10 damage. It's boring but it's the best choice if your priority is combat performance.