errProof - The website has a lot of useful and unique tools.
Wheel Decide - Wheel Decide is a free to use web-based spinner platform that allows the people create their own digital wheels system for prize giveaways, decision making, games and much more.
Getcalc - getcalc.com - online calculators, formulas & work with steps (step by step calculation) for expressions, statistics, probability, finance, health, geometry, general purpose & engineering calculations along with basic & scientific calculators.
RANDOM.ORG - RANDOM.ORG offers true random numbers to anyone on the Internet.
Insect - High precision scientific calculator with full support for physical units.
Wheel of Names - Free and easy to use spinner. Used by teachers and for raffles. Enter names, spin wheel to pick a random winner. Customize look and feel, save and share wheels.