I just finished with some Minecraft. I use an extensive set of mods on somewhat of a rotation. Java, of course. 1.12.2. There are tons of tiny mods that improve things, but for the larger ones I suggest 1) Blood Magic with Animus and Blood Arsenal. 2) Electroblob's Wizardery (with addon spells). 3) Atum. 4) Dungeontactics 5) Thaumcraft 6 with everything except Thaumic potatoes. 6) ProjectE (slightly OP) 7) Tinker's Construct with Tinker's Armory. 8) Botania is pretty decent too.
If you're going back to 1.7.10 then Thaumcraft 4 is still good, but Blood Magic isn't as great. Ars Magica becomes an option, and Draconic Evolution and EnderIO are (IMO) better.
Other than that be sure to grab NEI, JEI, HWYLA/WAWLA, WAILA Harvestability, betterbedrockgen, veinminer, journeymap, infinitefluids, Engineers Workshop (Reborn), Baubles, Clumps, Appleskin, Uncrafting table, and capsule.
Curseforge is my source for all of these. If anybody's interested I can try to add a zip file.