Artifact Rankings - Top 6 from 1 to 6 and why? Trying to find best application of artifact with game play.

For example"
1 - Army Camp Boost - Passive (WHY: continous higher percentage of armies created)
2 - Hospital Boost Bonus - Passive ( WHY: reduces amount armies required to take a territory)
3 - Territory Money Boost - Passive (WHY: continously increase $$$ to for upgrades and purchase of mercenaries)
4 - Draft Boost - Passive (WHY: Passive use every 6 minutes when Icon appears)
5 - Speed Smelters - Passive (WHY: Allows for faster production of alloys for Techs and selling for $$$ for upgrades)
6 - Army Camp Discount - Passive (Why: Save $$$ when upgrading Army's

I would argue that it is hardly possible to rank artifacts. Even if you exclude all the active artifacts (because these don't do enough to be worth 16h of a slot), the only thing you can do is classify the artifacts:
- There are (passive, as we defined) artifacts that increase your income of armies, money and ores
- There are artifacts that affect your smelting/crafting
- There are artifacts that affect building upgrades and techs in cost
- There are artifacts that affect territory capturing.
The territory capturing artifacts further classify - if you wish - into:
- Artifacts that affect capturing no matter what (e.g. Hospital Boost)
- Artifacts that affect territories with caches (e.g. Money Cache Boost)

I might have forgotten some. But what you can use this classification for is define which artifacts you use by default (like income or smelter/crafter) because they count every second they are equipped, and which you only need to equip in SOME situations like building upgrade/tech unlock/territory claiming.

This all, given that you are willing to swap them in and out each time you take the respective actions.

If you want to know three artifacts that you can keep in their slots for ever, I'd say army income boost, and the two money income boosts.

i had a rare draft boost artifact, and the best thing I ever did was sacrifice is to get an epic of another. yeah, you "can" drop it in and out to be more efficient. But then ever six minutes it's swap it in, find your draft icon, swap it out. I enjoy my life alot better without it. plus, drafts are worth alot less now. they used to be close to a quarter of my army total, but it's alot lower now.

1. Bonus Money Boost (More money plus only 2 tech that help) [a Poor Bonus Money Boost is about equal to a Uncommon Territory Money Boost as far as money, which is why it's the way better option]
2. Army Camp Boost (More Armies, though all the tech upgrades puts it behind Bonus Money Boost for me)
3. Mine Boost (great early to keep smelters running as much as possible and late game for the high end Alloys you need to make)
4. Speedy Crafters (Items sell for more than Alloys comparatively)

Huge gap after these four for me. The next four can be in any order for me.

Draft Boost (worth it for drafts following Army Caches or buying Mercenaries.)
Hospital Boost (might not be worth it for smaller maps, but really adds up on large maps.)
Mercenary Discount (more Armies for the same money.)
Item Values (more money.)

Another big gap, these eight are useful enough not to sacrifice, but not buy much.

Army, Money, & Resource Cache Boosts.
Ore & Alloy Values.
Army, Hospital, & Mine Discounts.

I don't think anything is worth keeping after these.

Territory Money Boost is trash. Territories give only ~10% of total money so bumping that doesn't do much. Bonuses give 90%.

I’m assuming you mean for the core game and not battles.

The “army” artifacts (Army Camp / Hospital Bonus) are obviously top tier.

Smelter and Crafter Speed are better than they seem - you only need to activate them for a split second in the 68% -> 100% range (depending on quality of artifact) to instantly complete the recipe. These are the best of both worlds for active/passive since they don’t have cooldown.

I don’t think anything else is in the running. Obviously there’s a bunch you can toggle on/off (Merc Discount, Cache Boost, etc.) but these are just nice to haves.