LOOK GOOD, RUN FAST
Complementary shaders through Iris, and the mods that keep your FPS up.
The pack ships Iris (the modern shader loader) with Complementary Shaders in both flavors: Unbound (transforming the visuals) and Reimagined (preserving vanilla's look with exceptional quality). Euphoria Patches extends Complementary further. Pick your pack in the video settings shader menu.
Motschen's Better Leaves improves foliage, and the Entity Texture and Model Features pair (ETF and EMF) brings custom, emissive, and varied mob looks.
Sodium, the fastest rendering optimization mod for Minecraft, plus ImmediatelyFast, Entity Culling (hides entities you cannot see), and Clumps (merges XP orbs). The pack is built to look like the screenshots without melting your PC.