rVMI - Debugger on steroids; inspect userspace processes, kernel drivers, and preboot environments in a single tool.
Frida - Dynamic instrumentation toolkit for developers, reverse-engineers, and security researchers.
Reverse Engineering CTF-like Exercises
https://microcorruption.com/ - Given a debugger and a device, find an input that unlocks it. Solve the level with that input.
http://reversing.kr/challenge.php - This site tests your ability to Cracking & Reverse Code Engineering.
https://www.malwaretech.com/beginner-malware-reversing-challenges - The purpose of these challenges is to familiarize beginners with common malware techniques.
https://crackmes.one/ - This is a simple place where you can download crackmes to improve your reverse engineering skills.
https://challenges.re/ - Well, "challenges" is a loud word, these are rather just exercises for RE.
https://reverse.put.as/crackmes/ - A collection of crackmes for OS X. Send them to me if you have new ones to add!
https://join.eset.com/en/challenges - If you want to join the team that every day faces global cyber-threats, uncover a hidden puzzle in the crackme program and prove us your potential.
http://flare-on.com/ - FireEye's challenge RE.
https://ropemporium.com/ - Learn return-oriented programming through a series of challenges designed to teach ROP techniques in isolation, with minimal reverse-engineering and bug-hunting.