I've done a lot of learning using both MineTweaker3 and ModTweaker over the last few weeks as I have been setting up a custom mod pack for personal use.
Of interest I've learned how to take unused assets in mods and integrate them into play.
The example I will give here. Note: This mod pack is only for my personal use. I will not distribute it. Any changes made are strictly for my use only.
Two of my installed mods are Garden Stuff and ExtraTiC (Tinkers' Construct compatibility addon)
Garden Stuff uses a proprietary furnace to create an "alloy' using sand and iron. I found this to be highly limiting as it required charcoal (not coal) to work. The resulting Wrought Iron ingots are only useful in decorative and lighting.
ExtraTiC adds all of the molten versions of Metallurgy 3 to the ore dictionary, but without the mod installed; does not add recipes to the smeltery for them. So they are not being used and normally cannot be accessed. Dark Steel is one of these.
Using ModTweaker and MineTeaker I added a recipe that converts molten Iron (1 ingot, 144mb) and molten Glass (1 block, 1000mb) to molten Dark Steel (1 ingot, 144mb) I then added casting recipes for Dark Steel in appropriate amounts to make ingots, blocks, and nuggets of Wrought Iron (they look very similar).
I further added melting recipes so that all Wrought Iron items can be melted down to their equal exchange millibuckets of molten Dark Steel.
This got me thinking:
What if there were a Resource ModPack that added a ton of unused items whose soul purpose was to just be available for MineTweaker/ModTweaker users to utilize so they could create new items on their own?
Additional liquids, materials, alternate items (doors, redstone components, buttons, levers), building blocks. Just a ton of unused items and materials that someone can add in to a game to fill in a gap, add variety, or make something new altogether. Generic Armors added using wool recipes, and then renamed to Sheep Skin Armor?
Anyway, I think the potential is endless and it would open up massive creativity potential.