I have a 2v2 scenario for the CCM2 Iberia map, its quite basic but was effective. Nothing too special tho.
I saw The Last Kingdom was mentioned so ill leave this here.. I have a patch for TLK. Its gonna need more work but I found out that its just crazy hard to balance. Unit stats are balanced already but the main problem comes with settlements. England, especially southern England has alot of good settlements but mostly just alot. Meanwhile Scandinavia barely has any, kind of screwing up the balance by quite a bit. To show you what I mean:
I also have some huge mods with Broken Crescent and falcom total war(Entire world from America to Australia HS) but those are probably too big
Picture of Britannia: