(A) Drifting deep into my houserules and blogs that made them!
No Clerics! I think any class could also be a cleric. Also there are so many different religions and beliefs I don’t want Christian-based one to be the only one with power. Yeah, give your pious fighter some clerical powers on 6+ levels!
https://deltasdnd.blogspot.com/2010/05/giants-in-earth-index.html
https://vdonnutvalley.wordpress.com/2021/12/19/bad-apples-in-classes-clerics/
https://deltasdnd.blogspot.com/2007/03/class-trouble-ii-clerics.html
Silver Standard! I think it was already a beaten to death but why not to undead it for a moment and familiarize more people with the idea! Basically – use silver instead of gold as a primary type of coin and price tag, let gold be special, to use for banking or only by nobility. You can make it cost even more than 10 x silver coins because it’s not primary way of payment and counting more crazy exchange rate is not going to happen too much.
https://methodsetmadness.blogspot.com/2023/04/low-fantasy-silver-standard.html
https://traversefantasy.blogspot.com/2023/09/normalizing-skerples-medieval-price-list.html
Thief Skills on 2d6! I don’t like using d100 so for me it is more of a cosmetical change. But with such scale you can actually make +X to Dex/Wis matter in them (it wound’t matter in d100 and would break X-in-6 skills).
https://dysonlogos.blog/2009/08/01/d6-and-2d6-thiefin-for-basic-dungeons-dragons/
Dolmenwood Saves! Just changing the names and removing Wands/Ray because I think it has very little usability.
https://necroticgnome.com/blogs/news/dolmenwood-core-rules
All 1st level spells known to Magic-Users from the start but none 2nd or higher level got automatically. Adventure for your magick, mate!
http://wheel-of-samsara.blogspot.com/2010/10/gedankenexperiment-vancian-rarity.html
Did I mention your wizard staff has some additional qualities now? Saruman it all the way! Magic staff now holds alternative spells to your memory so you have even better versatility!
http://jovialpriest.blogspot.com/2011/06/wizards-staff-and-wand.html
These are the houserules I use. Okay, some of them I learned only recently and only intend to use but still counts! And there are a few more for me to present but they’ll require their own posts.