Hello, in the Technic Launcher modpacks, I know Industrial Aether has many mods like Thermal Expansion 1 for 1.2.5, the exact ThaumCraft2.1.6d, Buildcraft, IC2, Factorization, EE2, Aether 1, railcraft, NEI for its time (when carrying the files to test if Codechicken and NEI work in other ways its a bit useless so just adding other 1.2.5 so than removing them isn't smart, I was just testing it a long while ago to see if they work outside the mudpack. But their are also other mods like the airship, ender storage, bees, redpower 2, ic2 addons, Wireless Redstone, nether ores, sneaky pipes, twilight forest, tubestuff and more. Try that. Technic has been my go too for any 1.2.5-1.7.10 modpack instances even if Java doesn't go for 1.7.10 on the standard launcher for me anymore. Try that out. I even made videos of mod versions content features using the 1.2.5 mods in it because a history of mods idea came to me at the time.
Or you could, use Lost Thaumaturgy for newer Minecraft versions, but its differences in areas compared to the original and its addon mod, isn't completely Thaumcraft 2 so Lost Thaumaturgy isn't for everyone.
Your welcome Thaumcraft 2 fans.
Also there are mods like Intermediary which do 1.2.5 mods for 1.7.10, but its messy and less useful.