Useful tools for 3D Printing

Calculator for 3D Printers
This tool is great for steps per mm, acceleration and Optimal layer height.

Convert pictures to STL format
You can sign up for free and get a low-quality STL for free. You can get higher-quality STL's for a price.

Hand tools
A good scraping tool will help you get your 3d prints off the heat bed. Any scrapper like this one would do the trick
A drill bit kit like this one will help you clean out your extruder when it gets clogged.
Flush cutters can really help with trimming pieces off your 3d prints.
Needle nose pliers can help with pulling supports of your 3d print.

Heated bed adhesion
painters tape can help stick PLA to a non-heated bed but not ABS.
Elmers glue sticks also work with PLA and sometimes works with ABS on a heated bed.
ABS juice works great with ABS on a heated bed.