I thought that some sort of expansions index could be helpful (especially for noobs like me) . I think about both - official and unofficial, rather compatible with 8th edition. Personally, I know about: Storms of Magic - magic heavy, with new scenarios Triumph and Treachery - for 3 or 4 players Regiments of Renown - skirmish battles Are there other? What are the pros and cons of them?
Yes, there are map campaigns, Siege games, and Monster Battles. Blood in the Badlands (sadly limited edition) has suggestions for map campaign rules and Siege games. Monstrous Arcanum (ForgeWorld) has rules for Monstrous scenarios. Basically, it's like Storm of Magic without the magic. Each side makes a normal army and then adds on 25% or 50% bonus points on scrolls of binding, though there are a lot of potential variants of the theme. I find Siege games to be a lot of fun though I only played two games, I'm itching to do more if I can find a willing opponent. I played two map campaigns with a lot of house rules. Problem with both map campaigns was that it did not have a mechanism to give underdogs a comeback. In both cases the player who discovered the campaigns meta first grew power so quickly that they literally became more powerful than all other opponents combined. The GW recommended system in the Blood in the Badlands incentivizes winning early battles but it doesn't give early victors an insurmountable lead towards the end.
Here is an incomplete list of all the GW/Forgeworld 'official' supplements to Warhammer Fantasy Battles that were made for the 8th Ed. of the game: Warhammer: Mighty Empires Warhammer: Storm of Magic Warhammer: Blood in the Badlands Warhammer: Triumph and Treachery Warhammer Scrolls of Binding Compendium Warhammer: Tamurkhan: Throne of Chaos Warhammer: Monstrous Arcanum Warhammer: Civil War Warhammer Battlefields: Border Wars Warhammer Battlefields: Lustria Warhammer Battlefields: The Underway Warhammer Battlefields: Northern Wastes Warhammer Battlefield Challenge: Skullvane Manse Warhammer Battlefield Challenge: Deathknell Watch Warhammer Battle: Vanguard Clash Warhammer Battle: Blood in the Snow Warhammer Battlescroll: Be'lakor Warhammer Battlescroll: The Restless Dead Warhammer Battlescroll: Creatures of the Chaos Wastes Warhammer Battlescroll: Crypt Scavengers Warhammer: Sigmar's Blood Warhammer: The End Times: Nagash Warhammer: The End Times: Glottkin Warhammer: The End Times: Khaine Warhammer: The End Times: Thanquol Warhammer: The End Times: Archaon I'm certain there are many that I have missed. I have not heard of the Regiments of Renown rules the OP is referring to (although I do remember something by that name in the 6th Ed.).
Yes, I think that RoR wasn't made for 8th, but can be easily transferred to it. Do you know where one can find those books in internet (I assume most of them cannot be bought now).