There are many educational sites online, some are free to educators and some are not. Here are few that might benefit you. Also, doing a Google search for 1st grade educational resources and the like will bestow many more.
General Resources
Education.com (learning games for VL students and teachers)
Google for Educator Help Forum (if you have issues, more than likely, others have problems too - check out the forum for fast answers)
Kahn Academy (free resources for educators - nonprofit organization)
Twinkl (free resources and more)
PBS Learning Media (videos, games, and more)
EdPuzzle (a plethora or resources, free and paid)
Math
Imagine Math (provides 100's of DL-based math lessons at your fingertips)
History
Best Educational Social Studies Websites (ideas and projects galore)
Science
California Academy of Sciences -Select your grade level (science lessons and more)
The Best Science Website for Elementary Students (videos, experiments, and more)
Language Arts
Teacher Vision (this looks like the backdoor to the service, but you will at least get an idea of what the company offers)
In progress . . .