I'm playing Accelerated DF with my own little tinkerings in the raws, and it's mostly vanilla otherwise. Although I'm thinking of adding some mods like the xenomorph mod, Fear the Night, and Wanderer's Friend. Also thinking of moving the item_weapons.txt from Masterwork to my copy of Accelerated for all the extra attack options, and editing the numbers so my dorfs can use pikes and halberds.
I'm thinking of making a metal ore called goblinite that when smelted has a chance of yielding copper, silver, iron, or bronze metal, just because I can, and I'm also toying with the idea of adding uranium and making silver and gold capable of crafting into armor.
Current edits in my Axehole fort include dwarven war cleavers and dwarven carving knives added to weapons(copies of the cleaver and carving knives items' files but moved to weapons.txt so I can craft them and assign them in Fortress mode to troops) and adding the [ITEM_THIEF] to the dorf's ethics. An interesting result is that every trade caravan of dorfs, when they leave the game is flooded with reports of "A thief has stolen *INSERT TRADED GOOD HERE*!" It led to some WTF moments, I can tell you that. Another side effect is all other civs are hostile to you, meaning you only get the dorf caravan. No migrants' professions listed as thieves though, which was my goal.
I also edited cats to be war-trainable so the catsplosions can be slightly more useful.
Oh, and no aquifers. Nope nope nope.