Use the following links to report phishing attempts, scams, abuse, etc. Please let me know if you are aware of others that should be added to the list.

PhishTank (operated by OpenDNS) is a great resource. You can redirect your phishy emails to them as well as the companies below.
https://www.phishtank.com/add_web_phish.php
Redirect phishing emails to: [email protected]

Apple
http://www.apple.com/uk/legal/more-resources/phishing/

Google
https://www.google.com/safebrowsing/report_phish/
https://www.google.com/safebrowsing/report_badware/
https://support.google.com/mail/contact/abuse

Amazon: [email protected]
Apple: [email protected]
Facebook: [email protected]
FedEx: [email protected]
Linkedin: [email protected]
Netflix: [email protected]
Paypal: [email protected]
Salesforce: [email protected]
Stripe: [email protected]
Wells Fargo: [email protected]

Government UK
HMRC: [email protected]
Information Commissioner: https://ico.org.uk/concerns/marketing/spam-emails/
Police: https://reportlite.actionfraud.police.uk

Other
decentsecurity.com
https://www.spamcop.net/
spamgrabber.org