The Smart Tutor, K12 Reader and Education.com websites have resources for improving a first grader's reading skills online. Each site has numerous free resources that cover various first grade reading topics, such as vocabulary, reading comprehension and silent letters.
Smart Tutor has a short list of free resources for first graders that use cartoon-style art to keep the kids interested while studying. The site has a paid model that offers more resources that can be purchased monthly or yearly. There is a 14-day free trial of the full service to test out the features before committing to a subscription.
K12 Reader has numerous downloadable worksheets that can be printed to supplement online work. The site also has graphic aids, lesson plans and lists of helpful books to help encourage and facilitate learning. Each worksheet has a short description of what it focuses on.
Education.com hosts games that are fun and help students get a better grasp on the topics covered. The site has pages dedicated to worksheets, activities and workbooks that offer a wider variety of options for reading skill help than some other sites. Many features are available for free with a basic account, but more things are available with a paid subscription.