Flaming Sphere and Spiritual Weapon work in the same manner, last I checked. Both got initiative, Health, etc. So enemies tend to focus on them. As for the items, RAW 5e most don’t work for Moon Druid, which is fine. However in recent books, many feats and items are added, which work really well, here are some examples from rpgbot.
Link:
https://rpgbot.net/dnd5/characters/classes/druid/#magic-itemsMagic items:
1. Barrier Tattoo (Uncommon)TCoE: Most druids should stick to studded leather unless you can get a better tattoo, but Circle of the Moon may find that this boosts their AC in certain forms.
2. Barrier Tattoo (Rare)TCoE: AC is among the Druid’s biggest problems, and matching the AC of Half-plate without wearing metal armor is an absolutely massive improvement to the Druid, especially since this works in Wild Shape. It hurts that it costs a Rare item to do it, but it’s hard to argue with how effective this is.
3. Belt of DwarvenkindDMG: Maybe appealing for Circle of the Moon, I think this might still apply during Wild Shape. Adding Darkvision and poison resistence to beasts which don’t normally get it is really nice, though the +2 Constitution won’t have much impact since your beast forms will have few hit dice.
4. Belt of Giant Strength (Hill)DMG: This works while using Wild Shape, which is mechanically amazing and conceptually hilarious. Imagine using Wild Shape to run into a mouse with 21 Strength. Once you’ve had a sensible chuckle about that, consider how many wild shape forms give up some Strength-based attack and damage bonus for durability or special abilities (Pack Tactics, Flyby, etc.).
Feats:
1. Gift of the Chromatic DragonFToD: Chromatic Infusion should be shared with allies unless you’re going for Circle of Spores, and even then your allies with Extra Attack will benefit more. Reactive Resistance is largely redundant with Absorb Elements, but it’s uniquely appealing for Circle of the Moon since you can use it while wild shaped.
2. Gift of the Gem DragonFToD: Great for Circle of the Moon because you can use Telekinetic Reprisal while Wild Shaped. Circle of Spores might also benefit, but you already get a way to use your Reaction every turn so there’s little need for this in your action economy.
3. MobilePHB: All of the effects apply while you’re in Wild Shape. Forms like Goat and Elephant which have a useful Charge or Pounce effect become immensely more useful when you can safely move away and set up for another round of charging. If you just need an escape mechanism, look for Wild Shape forms with Flyby like the Owl and you won’t need to bother with Mobile.
4. TelepathicTCoE: Tempting for Circle of the Moon, this nicely solves the issue of communication while using Wild Shape, and since you still get a Wisdom increase the feat’s cost is reduced.
As you can see, most of the items aren't even that rare. Per rpgbot: "In my opinion, anything which is part of your character’s body like claws, natural armor, or damage resistances doesn’t work while in Wild Shape. Anything your character knows, like proficiency in something, specific training granted by a feat like Mobile or Actor, or something inherent to your character’s personality, culture, or anything else non-physical like the Lucky feat or the halfling Lucky trait should still apply in Wild Shape. But, as in any case where there is a question, your Dungeon Master makes the final decision. Be sure to talk to your DM before making any decisions about your build."
