Great Online Resources!
Look through FULL Practice Sets!
Math
AOPS (AMC 8 Practice sets): https://artofproblemsolving.com/wiki/index.php/AMC_8_Problems_and_Solutions
Science
Science Bowl's Official Website (Great for practicing your skills): https://science.osti.gov/wdts/nsb/Regional-Competitions/Resources/MS-Sample-Questions
Math
AOPS (AMC 8 Practice sets): https://artofproblemsolving.com/wiki/index.php/AMC_8_Problems_and_Solutions
Science
Science Bowl's Official Website (Great for practicing your skills): https://science.osti.gov/wdts/nsb/Regional-Competitions/Resources/MS-Sample-Questions