Take a virtual tour of various colleges/universities (Harvard, Yale, University of Southern California, University of Kentucky, etc.)
ACT / SAT
https://www.march2success.com/ - Practice tests for ACT; Practice tests for new SAT will be coming soon!
ACT Practice - Vocab, guides, etc.
CollegeBoard - Official SAT website; Practice for new SAT.
Khan Academy - Practice for new SAT tailored to your abilities.