CB's overview:

https://collegereadiness.collegeboard.org/sat/inside-the-test/study-guide-students

SAT tips:

https://docs.google.com/document/d/13rPjb7VsuMHQ_xazH7nEzo0_cGTs751Vg4wTidChARE/edit

1600.io:

https://1600.io/p/strategy

Compilation of books and practice tests;

https://drive.google.com/drive/folders/0B1WNUX-O8FMURVNqZHVMak5Qbm8

Prep books:

https://drive.google.com/drive/folders/0Byxoof4V9z7lbEpHOTFkUzgyWTQ

A quick plan:

https://www.reddit.com/r/ACT/comments/7zhdtl/my_act_prep_plan_for_a_36_or_really_a_plan_for/

SAT Grammar rules:

http://thecollegepanda.com/the-18-sat-grammar-rules-you-must-know/

ACT tips that work for the SAT:

https://pastebin.com/GL8jSDVn

All tests ever published legally:

http://thecollegepanda.com/complete-test-links/

KA (do the daily SAT prep):

https://www.khanacademy.org/test-prep/sat/full-length-sat-1/paper-sat-tests/a/full-length-sats-to-take-on-paper

SAT Action Plan:

http://www.mcelroytutoring.com/blog-post.php?id=1399&title=SAT+Action+Plan

SAT Math guide:

https://docs.google.com/document/d/1VwW2zHmNJMvv6gJovJHeFSDBTc7P2b-jBNJt2HJgKF0