Post release note: Thank you for your kind comments, I mostly made this for me so having so many people be enthused about the books and items makes me happy.
This is probably my 'magnum opus' as far as BG3 modding goes, but I will be doing other stuff too in future too.

What is it?
This is a mod that adds items with a Lathander theme. They have been placed around the world in appropriate chests and vendors, and also in the tutorial chest.
It started with me wanting a shield to match a certain mace, then I added other things too.

Weapons and Shields

• 3+ Shields
• Spear
• Restored a cut Morningstar. I gave it a new name and description, in case you have another mod that re-adds it.
  

Armour

• Half Plate Set
• Scalemail Paladin Tabard
• Endgame Heavy Armour set
  

• 3 Circlets
• 2 Capes
• 5-6 rings and necklaces
  

Lore

• Books and notes scattered around the world to add to your roleplaying experience! All of the lore is sourced from the forgotten realms wiki, nothing completely invented, and is presented from biased perspectives. So you can simply ignore it if you don't like it.
  

And More!

• 'Idols of Lathander'. Sell it! Use it as camp decoration. Put it in that tent you don't have.
• Starter pack for your Level 1 character in the tutorial chest.
  

All armour items can be dyed. The armour and accessories are available to every race and gender combination plus Wine and Revelry Satyr race, with a few exceptions- the circlets don't work for Dragonborn female or strong tieflings. I am limited by what meshes are available in the game files. The halfplate looks odd on females or some other races also.

The stats for the equippables are largely geared towards life or light Clerics and Paladins, with a sunlight and anti undead theme.

Each item's gold prices have been set by the game's own method of generating costs, so they should be consistent with the game's usual pricing of similar items.
A certain shield is equippable only by Lathander worshippers, to make you feel a little bit more of a special sunflower. All other items can be worn by anybody.

Where is it?
The items have been placed around the world in chests and vendors. I have placed things with an effort towards immersion, so weaponsmiths only have weapons, booksellers only have books and so on.
All the items are also in the tutorial chest. If you have passed the tutorial chest, you can use a mod like this or this or this to access the chest.
There is a 'master chest' in the tutorial chest, which contains two containers. A box with all the high level stuff, and a basic backpack with just a few low level items, for balance.


Some of the places in the world the items can be found:

(Once a worldspace has been loaded, its chest contents are loaded also. So you would need to restart the level in its entirety to regenerate chest contents. For this reason, I have not actually tested most of these locations. Please let me know if stuff is spawning where you think it shouldn't.)


Compatibilities

• This mod just adds to existing treasuretables and does not overwrite anything, so should be compatible with anything else.
• No edits have been made to the 'Blood of Lathander' item, so any mod that alters that weapon or its passive will work.
•  Any mods you have affecting the 'Lathander's Light' passive will also work on the spear in this mod.
• If you have a mod that adds Amauntator as a diety, you might be able to equip the restricted shield depending on how the game responds to modded God tags. It might not work, but I at least added the possibility.
  

Known Issues

• The cloaks get dirty fast. This is because the dirt/blood overlays build up more with the modder-available shaders for whatever reason. I cannot fix this, so maybe look into one of the mods that disables the dirt overlays or auto applies soap if this becomes a nuisance.
• The Rosemantle spell has slightly incorrect text when hovering over a creature. It shouldn't affect the spell itself.
• If you have Disguise Self on, you cannot equip the restricted shield. The reason is that the Disguise Self spell removes your character's god tags. I would consider this a feature/bug of that spell, so I will not be changing anything in my mod to accommodate it. (If you use the Whispers of the Fey - Changelings Race mod that should be fine, as that mod has its own custom disguise self spell.)
  

How to Install
I recommend you install this with BG3 Mod Manager. A guide to BG3MM installation of mods can be found here. Mod Fixer may be required.

This mod can't be safely uninstalled mid playthrough. This is because it adds new items in a lot of different places. If you remove an item mod mid-playthrough, your save will not know what to do with broken references to an item that no longer exists, and may refuse to load at all. I cannot help you with any issues that result from uninstalling the mod after you have begun a playthrough.

Questions you May Have

These item stats are underpowered/overpowered.
I may tweak stats or placement if people are unanimous about a certain item being good or bad, or overpowered for where you get it, but ultimately this mod is focused towards roleplaying enjoyment. So if you want game balance to be exactly like the original game, you may prefer to give this mod a miss.

Will you make anything for [Insert Name Here] God?
Probably not, definitely not anything of this scale. If I make something for a God depends on a) If I like them (most important factor), and b) If they have any useable art assets in the game. (Many of them don't, sadly)
Lathander has a whole monastery and I like him, so I made a lot of stuff for this mod.

Will you add something new for [X] class or weapon type here?
You can mention it if you like, but there's no guarantee I will do it. This mod is already way bigger than I thought it would be.

When I installed this mod, I found myself in a room full of naked men plus a dragonborn...?
You lack Mod Fixer, you need to install/ reinstall it.

Can I have a version of this mod that is tutorial chest only/doesn't have the books/only has [item]?
No, there will only ever be one version of the mod.

Can I edit this mod for personal use?
You can, for personal use, unpack the mod and change it around to your liking, so long as it stays on your harddrive only. However, in doing so you accept that I can no longer help you if you run into any issues with the mod. As you have 'voided the warranty' so to speak.
I would also politely request that you not put discussion on how to edit the mod in my comment section.

Future Plans for this mod

• If it becomes possible to test adding things in levels more easily, I will look into putting some of the items in the worldspace itself instead of just in containers.
• When it becomes possible to import weapon armatures without data loss, I will redo the shields so they clip less with the hands on some body types.
  

Other God mods by me
Always succeed religion check for your clerics and paladins
Cleric Camp Outfit
Helm's Armory

Cool mods by other people
Dyes of Faerun (Desert Sun dye scheme is used for most of the items in this mod.)
Victor's Outfits- Lathander outfits
Permissions
I do not support any reuploaded edits to this mod (its models, texture assets, code, txtfiles), on nexus or discord or wherever else. If it's just for personal use that is ok.
However feel free to make a localisation, so long as your .pak upload contains only a .meta and .loca files.

Credits and Thanks
Thank you to:
Celestialspider - lovely pictures
Aloija for the armour colour values from her Dyes of Faerun Desert Sun dye.
Ethicalcrusader - helped come up with some stats which I have added to the best of my ability
Norbyte's invaluable search tool and code validators
Kaz- Added Book Template and fixing spear armature
Solbera Dnd Fonts
+ everyone who helped my coding or encouraged me.