Call of Duty: Vanguard

Zombies Mode - Requires an online connection even if playing Private Solo matches!

All of the artifacts referred to in these four achievement descriptions are items that you can equip in your gear loadout, meaning you start each game with them. They are not obtained from inside the match itself. 

As a result, every single one of these artifact achievements can be unlocked on Wave 1. Also note that all of these achievements are cumulative across all games played. All of the artifacts work the same way in terms of usage: you must kills zombies to "charge" up the artifact (circle meter in the bottom right that fills up white as you kill zombies). Once it's full it'll flash and you'll see "+" under it now, meaning you can press those buttons to use it. After using it, you need to kill zombies again to recharge it before you can use it again. Therefore, all you need is an endless stream of zombies and you can grind out each one of these achievements on Wave 1 in a single session.

The only source of an endless stream of zombies is in the Harvest portal objective. These portals require you to pick up relics dropped by killed zombies and place them inside a machine. If you don't place them in the machine, zombies just spawn endlessly until you do so. You can therefore ignore the objective in a Harvest portal and just farm zombies over and over. If you're doing this on Wave 1, I recommend advancing to at least the second round in the Harvest portal (you need to place five relics inside the machine three times to complete the portal; do so once to advance to the second round in the portal) because zombies will spawn faster and move faster, allowing you to get kills faster (don't worry- they won't be anywhere near too fast to handle, especially on Wave 1).

Some quick points about each artifact, in terms of its achievement.
 

• Frost Blast Artifact (As Cold As Ice (30G)) - this one is the biggest pain, because you need to use it, have it freeze enemies, and then melee the frozen enemies to kill them. The problem is that enemies very close to you when you use this artifact will die immediately. You'll then drop a sort of ice swirl on the ground around you. This swirl lasts for only a couple seconds. During that time, you need zombies to walk into it far enough so they get frozen. They only stay frozen for a couple seconds, so you then need to quickly melee them. So actually, for this artifact, the faster the zombies are moving, the better, because slow zombies need to be far enough away to not die when you use it but close enough to reach it before it expires. Even on Wave 1 you get the occassional sprinter though, so ideally wait for them. Use the artifact a bit away from the zombie(s) so it doesn't kill them, move towards them to place the swirl closer to them, back away and watch, look for any zombies to ice up, and then quickly melee them to kill them. This is the most annoying and longest one, so be prepared for a bit of frustration getting the kills for this artifact.
• Energy Mine Artifact (Shocking Behavior (15G)) - despite what the description says/implies, the mine itself can kill enemies and still count towards this achievement. That makes this one quite easy - ideally, group up as many zombies as possible, then let them get near you and use this artifact, which will kill them all. Highly unlikely you'll need more than two or three uses of this artifact to get enough kills for this achievement.
• Aether Shroud Artifact (Escape Artist (15G)) - this artifact, when used, makes you invisible for a few seconds, so zombies lose track of you and run away. As the description says, you need to use it when you have less than 25% health, a cumulative total of five times. This is still relatively easy to do - assuming you haven't gotten the Red perk yet for increased health, nor crafted any armor yet, you can take four hits before being downed, so for this achievement, you need to get hit three times and then use the shroud. If farming this in Harvest, zombies typically come in groups. Kill all but one, check your minimap to make sure more aren't about to attack you, and let that zombie hit you three times. Right after the third hit, back away, kill it if you want, and then use the artifact before your health starts regenerating. Repeat four more times.
• Ring of Fire Artifact (Hot Tempered (15G)) - when you use this artifact, it places a purple ring of fire on the ground. Shooting from inside the ring of fire gives you a damage boost. So this is one of the easiest achievements to get, because the ring lasts pretty long - you may even be able to get it in a single usage. Just make sure you're standing in the ring of fire while shooting to get credit towards this achievement.