One piece of software I consider indispensable for keeping my Mac running clean, quick and clear is CleanMyMac X by MacPaw.
CleanMyMac X packs more than 30 tools for keeping your Mac in tip-top condition, but is especially useful for clearing disc space, freeing up RAM, and deleting malware and adware. The latest version has a new, unlimited seven-day free trial, and Cult of Mac readers can get an exclusive 10% discount.