So there was an app for Mac users that allowed you to store your copy/paste history. This app was stopped/shutdown? and unavailable. I managed to get a copy of it from a former colleague [https://github.com/mpittau] that works and am making it available for others to download. Simply download, unzip and drop it in your Mac's main Applications folder. Open the app, and it should appear on your menu toolbar next to the clock/wifi controls, etc.
It is, hands down, one of the most useful apps I use day to day since it will save you from RSI switching between mouse and keyboard non stop when you want to copy paste something that you've since overwritten with a new item you've copied. It will save you time and effort when copying and pasting code/urls/variables/etc. Can't live without it now.
Ctrl + Shift + V - bring up the clipboard history. Use preferences to change the shortcuts and increase the clipboard history - 50+ items is recommended vs. the default value.