For those that wish to move beyond the medieval realm of vanilla Minecraft! Take note, many of these texture packs change how the Minecraft world looks considerably, it's very easy to get confused.
I would recommend using these only for single player, creative worlds, or as a fundamental server requirement to avoid potential misunderstandings. Some of the texture packs will recommend additional mods to download, so be sure to follow their instructions.
10. Craft Boy
If you're as old as I am, you remember the days spending hours playing games on your brick Gameboy earning neck cramps and replacing the 4 AA batteries that it required. This texture pack takes you way back.. It doesn't just have the same green monochrome color theme, but the blocks themselves have that classic Nintendo art style.
Have you ever wanted to go to the moon? Eat cheese on the moon? Dream of electric sheep? A very old pack that I am happy to see still around and updated. The_Fool76 also has 3 other texture packs to take a look at, which you will see in the link provided.
8. SMP's 2263: A Sci-Fi Texture Pack
A drastic change from regular Minecraft, many blocks look nothing like what they were originally. It's absolutely perfect for building a futuristic science lab.
7. Aleph Setei
Another sci-fi pack, only this one takes you to a strange alien world. Very futuristic, and creative.
6. Precisely Portal and Modified Portal
Enrich your Minecraft experience! There are limitless opportunities for experiments and testing, enough for someone to make a working Portal Gun mod go with this.