The class guide states:

Replicable Items (2nd-Level Artificer)

However, when I look at the list of options for selecting items, I get A LOT more options to use, IE, a Cloak of Billowing. Is this just a Beyond issue, or are able to actually use the anything that pops on that list? 

I feel like this might be one of those moments where "Just because beyond allows it, doesn't mean its correct."

Using this infusion, you replicate a particular magic item. You can learn this infusion multiple times; each time you do so, choose a magic item that you can make with it, picking from the Replicable Items tables below. A table's title tells you the level you must be in the class to choose an item from the table. Alternatively, you can choose the magic item from among the common magic items in the game, not including potions or scrolls.

You can choose an item from the replicate magic item tables or you can choose any (non potion, non scroll) common magic item.  The Cloak of Billowing is a common magic item and thus a valid choice.

This text appears in Tasha's Cauldron of Everything and the Eberron Rising from the Last War (since the errata).

Oh Jesus I totally missed that part.  

At present that means that, by RAW, you could replicate the spellwraught tattoo with a cantrip or L1 spell. There is a whole other thread on that if you want to read through it. However, don’t be surprised if your DM rules that it is a disposable item like a potion and scroll. The reality is that with just 2or 3 infusions available to be active your not going to want to use that anyway. Better to make sure your weapons and armor are as battle ready as possible.

@soulysephiroth, I've used the 'Replicate Magic Item' feature in order to replicate the magic item 'Ruby of the War Mage' for my Artificer PC. This is also a good choice since the common magic item will let my PC cast spells using weapons. As a result she doesn't need to hold tools for spellcasting and can immediately cast spells during battle. So, take advantage of the additional options and always consult with your DM.

The magic item mentioned above can be found in the source book 'Xanathar's Guide to Everything', so you have more options to choose from.

Quote from Stoutstein >>

That would be mostly redundant because artificers can already use any infusion as a spellcasting focus.

 We're discussing about selectable options, so it's not necessary to make judgment based on the importance of certain magic items. I've mentioned the use of 'weapon' as a spell casting focus. If it's a two handed weapon but not infused, then you don't have a free hand to cast a spell.

Thanks for the feedback.

Two-handed weapons only require two hands during the action of making an attack.  You're always able to take a hand off the weapon for casting purposes.

There are niche situations where the ruby of the war mage could be useful (primarily turning another party member's weapon into a focus for casters that cannot do so on their own, such as Bladesingers) but the artificer themself will rarely need the ruby for their own casting.  One fun notion I've not seen used before is creating Goggles of Night and treating your spells as various forms of Cyclops-style (the X-Man, not the monster) eye blasts from your arcane visor, tuned with a profusion of knobs and switches along the sides.  A classic is pulling spell gadgets out of an infused Bag of Holding.  And several other notions work as well; options on the level 6 list include the Gloves of Thievery, which become invisible 'bare-handed' spell foci for the artificer whilst heavily boosting their thieves' tools checks.

If you badly want to use an existing two-handed magic weapon as a focus, then yes - Ruby of the War Mage does the job.  Considering it eats an attunement slot, I'd try to avoid it if I could in favor of the numerous other means artificers have of attaining unique spell foci.

Yep, for an artificer, it will be more useful to infuse an enhanced weapon and/or use enhanced defence on your shield or gauntlet inclusive armour.  The only exception to this is if you already have conventionally magical armour, shield and weapon as, RAW, infusions can directly only be worked into mundane items.

Some artificers (mostly those of non-gish types) may typically not use weapons other than as a reserve for cases such as when opponents are resistant to the damage dealt by magics such as shocking grasp or, in that case, if there is also a reason not to touch.  

Quote from Yurei1453 >>

Two-handed weapons only require two hands during the action of making an attack.  You're always able to take a hand off the weapon for casting purposes.

There are niche situations where the ruby of the war mage could be useful (primarily turning another party member's weapon into a focus for casters that cannot do so on their own, such as Bladesingers) but the artificer themself will rarely need the ruby for their own casting.  One fun notion I've not seen used before is creating Goggles of Night and treating your spells as various forms of Cyclops-style (the X-Man, not the monster) eye blasts from your arcane visor, tuned with a profusion of knobs and switches along the sides.  A classic is pulling spell gadgets out of an infused Bag of Holding.  And several other notions work as well; options on the level 6 list include the Gloves of Thievery, which become invisible 'bare-handed' spell foci for the artificer whilst heavily boosting their thieves' tools checks.

If you badly want to use an existing two-handed magic weapon as a focus, then yes - Ruby of the War Mage does the job.  Considering it eats an attunement slot, I'd try to avoid it if I could in favor of the numerous other means artificers have of attaining unique spell foci.

 Firstly, imagine that an artificer attacks with a two-handed weapon then attempts to cast a spell that requires bonus action and spell casting focus. The movement of taking a hand off the weapon to pull out a spellcasting focus will expend another action called '[Tooltip Not Found].

Secondly, the idea of replicating Goggles of Night is actually fantastic. An artificer can replicate Dread Helm and wield firearms, it will definitely resemble a particular superhero from Marvel.

Finally, PCs playing in a low magic campaign doesn't need to attune to a lot of magic items, also think about a low level campaign where magic items are rare.