There are over 100+ mods that make the game feel compleatly differant, while still giving that minecraft vibe. Some mods make the game more difficult, like Ice and Fire to add a late game challenge, Alex's mobs and Caves for a lil bit of nature, Critter Armory to protect you best pals, and many of YUNGNICKYOUNG's structure mods, Finaly to make it spicey there is L_Ender's Cataclysm and Mowzie's Mobs for bosses, Deeper and Darker and The Twilight Forest for dimensions, And Oh The Biomes We've Gone + Mystic's Biomes for a beutiful landscape. Maybe you'll even be able to make your own pocket dimension. (Who knows)
If you have ANY suggestions for mod you want added, leave a comment, and let me know of optimization mods I could add.
Thanks for you time, Kerfufflyy.

