Like all previous titles, Thrones of Britannia is very receptive to modding, so the sizeable TW modding community wasted no time pumping out essential quality of life improvements and custom content. Here are the best mods the fans have produced so far.
Total War Saga: Thrones of Britannia Mods - Better Camera Mod
Created by: kam2150
Right away we have a utility mod that, rather than adding to the game, simply makes it more playable. This camera mod allows you to zoom in and out further than usual, and without unit models disappearing. Additionally, it maps a hotkey for UI toggle. Not only does this benefit people who want to make neat screenshots, but also helps you get a better overview of the battlefield. This mod, from the same author, is also available for previous Total War games.
Total War Saga: Thrones of Britannia Mods - Unlimited governors
Created by: WLightWHeat
Thrones of Britannia caps the number of governors you can have at any given time at 10, which will make managing your realm more difficult as you expand, and can be quite limiting. This mod simply removes that restriction and allows you to have as many governors as you want, which will increase the measure of control you can exert over your territory. This mod will work with all factions.
Total War Saga: Thrones of Britannia Mods - Shields Down While Marching
Created by: Filay
Bringing back a small but important visual detail that was present in older Total War titles, but not in Thrones of Britannia, this mod makes it so that units keep their shields down at their sides when marching outside of combat - like real soldiers would. No need to lob those huge shields in a defensive position when there is no danger, right?
Total War Saga: Thrones of Britannia Mods - Longbow Animations Bugfix
Created by: Mr. Jox
Instead of waiting for a patch to probably not fix a bug, you can always rely on mods. Basically, in the vanilla game, there is no animation for the bowstring being pulled. The archer cocks the arrow, pulls it back while the string remains straight, then it teleports into his hand - because the string isn't dynamic and the game just uses two 3D models for the bow. This mod changes that, and the string is actually pulled.
Total War Saga: Thrones of Britannia Mods - Diplomatic & Occupation Options
Created by: Dresden
You know how most Total War games have deep diplomatic mechanics? And how Thrones of Britannia doesn't? This mod seeks to make improvements on that front. While it isn't a full diplomatic overhaul, it does add annexation options which rely on a number of factors depending on faction, such as legitimacy and military superiority. This will allow you to, in some cases, take over new territories without combat.
This list will be periodically updated with new mods.