Essential Tool 1: Rotary Tool
A rotary tool uses a variable high-speed motor to turn any number of attachments that fit onto a spinning bit. This is a pricier essential, but well worth it because of its versatility. Plan on spending anywhere from $30 to $130, depending on the accessories you opt for.
With a rotary tool, you can cut light materials like fiberglass and ceramic tile. Use the sanding attachment for use in tight spots. Use a grinder attachment to remove grout or file down burrs on metal edges. Stripped screw heads can be cut off using a spinning blade. You can strip paint and varnish from wood with sanding attachments and sharpen tools with the grinder. They're also handy for arts and crafts, and you can even cut your dog's toenails if they don't mind the sound.
Note: The motor spins at speeds up to 35,000 RPMs, so you need to be careful and always wear eye protection when using this toolbox essential.