A simple, light modpack that I have been personally using, so figured I might as well upload it. The pack focuses on improving terrain generation with OTG and Vanilla Vistas or Biome Bundle, improving cave generation with Yung's Better Cave's (though your preferred cave generation mod will most likely work), making the world more alive with Mystical World, Exotic Birds, and Animania, as well as much much more using the likes of Quark, Coral Reefs, and Pam's Harvest Craft! A full mod list is below:
Animania by Purplicious_Cow_
Aquaculture by Shadowclaimer
Biome Bundle by mc_pitman
Coral Reef by primetoxinz
Exotic Birds by ThePavoReality
Future Versions by TipTopGamingOfficial
Journey Maps by techbrew
Just Enough Items by mezz
Mystical World by EpicSquid319
Open Terrain Generator by team_OTG
Pam's Harvest Craft by pamharvestcraft
Quark by Vazkii
Vanilla Vistas by mc_pitman
Yung's Better Caves by YUNGNICKYOUNG