Dynamic FPS automatically reduces the speed at which minecraft renders when it's not focused (to 1 FPS) or hidden (no renders at all). It also fixes a bug in Vanilla Minecraft that makes it take much more performance in the background than it should.
Spice of Life: Carrot Edition
A mod designed to encourage dietary variety; it does so by rewarding the player for eating a variety of foods instead of punishing them for failing to diversify. Instead of using the stick, we use the carrot!
I am not this mod's original author, but I currently maintain it and as such am the main person working on it.
A mod that helps you avoid adding giant mods for single features by adding only those nice features.
Resolution Control allows you to render Minecraft's 3D portion (i.e. the main game, but not the HUD/GUIs/etc.) at a lower resolution, using nearest-neighbor upsampling. It even has a snazzy settings screen (open by pressing P by default) allowing you to adjust this as you go.