For tools that you don't know how to use, go cheap. That way if you break it while learning how to use it, you can replace it easily. Then, when you know how to use it and what to look for in a quality tool, buy the best that you can afford when you need to replace the cheap one.
Safety Glasses come in many shapes and colors. Good ones should protect the sides of the eye as well as the front. They are relatively inexpensive. Buy them online or at your local hardware store.
Your spatula needs to be very sharp to wedge in under parts that are stuck to the build plate. Be sure to wear safety gear (eye and hand protection). They are relatively inexpensive. Buy them online or at your local hardware store.
They should be lightweight but strong enough to protect your hands from a slipped paint scraper or craft knife. They are relatively inexpensive. Buy them online or at your local hardware store.
Used by machinists to measure small distances accurately. We use them for measuring calibration prints, filament diameters, and other printer tuning activities. Get one that is 6 - 8 inches (15 - 20 cm) long. Ones with digital readouts are easiest to use. This tool can get expensive; start out cheap. Buy them online.
We use these for removing support material and cleaning up printed parts. Try to find ones with narrow triangular blades to get into small spaces. Buy them online or at a local hardware store.
Buy them online or at a local hardware store.
A set of precision screwdrivers will serve you well. Buy them online or at a local hardware store.
Buy them online or at a local hardware store.
This is not your hair dryer. Used for paint removal and possibly solder reflow. A quick pass with a heat gun melts away filament strings in seconds. An inexpensive one will do. Buy them online or at a local hardware store.
Used for grub screws, various adjustments. Look for an assortment including M2-M8 at least. Buy them online or at a local hardware store.
Used to remove the nozzle from the hot end. Buy it online or at a local hardware store.
Often found in TV & radio repair shops back before flatscreens. We use them to adjust the current delivered by the motor drivers. They are basically non-conductive jewelers screwdrivers. Buy them online.
Used to test voltages and tune motor driver current. With a temperature probe, you can validate the temp on the hot end and heated build plate. You don't need to go too expensive on this. Buy them online or at a local hardware store.
When you need to rebuild your wiring harness, or replace that limit switch, a soldering iron and associated tools becomes really useful. You don't need to go too expensive on this. Buy them online.
Walter has his own list of essential tools (with better pictures)