Better with Shaders is a pack that features many mods, all client side (for optimal single player and multiplayer compatibility) that focuses on making your world feel more alive.
For the most optimal experience I recommend the use of BSL Shaders (This pack is designed for higher preforming PC's and while still usable without one it may not feel as alive without shaders installed)
The download does include BSL Shaders in the folder as a preset, but you still will have to enable it.