These are website that I have found very useful in my teaching career!
http://starfall.com
This is a great website for primary school ages. It is fun and interactive. I use the abc activities at the beginning of the year as we concentrate on one letter at a time. As the year progresses, there are many activities that keep students interested and challenged. Students can nagviate this website very well indepdendantly. They have great seasonal games for different times of the year. My students really enjoy all of the math games in the math area as well
https://www.teacherspayteachers.com
I use this website all year long! It provides the most amazing resources made by teachers. I have favorite teachers that I follow so I know when they have posted new materials. There are resources that you can purchase or some are even FREE! I love supporting other teachers who creating such amazing materials. This website is very easy to use and you have materials you need in seconds!
https://www.pinterest.com
I know at first it might not sound like a teaching website, but I always find tons of ideas for arts and crafts on Pinterest. This website also has a ton of great teaching ideas, along with teaching articles and acess to teaching blogs. I have a teaching board that I can virtually pin ideas on, so I can get access to them whenever I need! Its very mobile friendly as well, so I can quickly look up something on my phone if needed.