If you browse the internet everyday like I do there are a select group of websites you visit almost everyday, so why not make your new tab page have links to these websites to help you save time? Even if you choose not to use a custom built new tab you can use any website as your new tab.
Why
The easiest way to show you why you should use a custom new tab page is to show you what my homepage and new tab looks like.
This is what I see any time I open a new tab or a new window in my browser. As you can see there are three boxes broken down by category, each with their own title and items. Each one of these items is a link to a webpage I commonly use in that category. Above those boxes I put the Arch Linux logo (as Arch Linux is my default OS).
This is just a sample of what you can do. This works by loading a webpage (either local or remote) upon the opening of a new tab or window, meaning you can wield the full force of any HTML, JavaScript, PHP, etc you can normally use in a webpage because it is a webpage. Like I said above, this also means you can use ANY webpage such as Google, or a random Wikipedia page (https://en.wikipedia.org/wiki/Special:Random).
How
Firefox
1. Download and install the Custom New Tab extension2. Select the "hamburger" menu in the top right > Add-ons > Extensions
3. Select the "Preferences" option on the Custom New Tab extension and enter your custom new tab URL and choose any other option you want
After all your preferences are set your custom new tab page should work!
Notice: there is a slight delay if you choose the "Place focus in URL bar" and "Make URL bar empty" options, meaning some of your text will be erased if you start typing before the URL bar is cleared.
Chrome
1. Download and install New Tab Redirect2. Select the "hamburger" menu in the top right and select "Settings", then select "Extensions" along the left
3. Under "New Tab Redirect" select "Options" and enter your custom URL
 After all your preferences are set your custom new tab page should work!