All modern browsers have extensive keyboard shortcuts:

I tested every shortcut, and here's my list of keyboard shortcuts that work in all browsers – or, for the rare keyboard shortcuts I found especially useful, those that work in at least two of the above browsers.

Standard toolbar buttons Alt + ← , or Backspace

Back Alt + → , or Shift + Backspace

Forward F5

Reload Ctrl + F5

Force Reload (no cache) Esc

Stop Alt + Home

Homepage Ctrl + N

New browser window Address Bar Alt + D , or Ctrl + L , or F6

Set focus to Address Bar Ctrl + Enter

Add "www." and ".com" prefix to Address Bar Alt + Enter

Open Address Bar location in a new tab Tabs Ctrl + 1 … 8

Switch to nth tab Ctrl + 9

Switch to last tab Ctrl + Tab , or Ctrl + Page Up

Switch to next tab Ctrl + Shift + Tab , or Ctrl + Page Down

Switch to previous tab Ctrl + W , or Middle Click tab, or Ctrl + F4

Close current tab Ctrl + T

Open new tab in the foreground Ctrl + Shift + T

Reopen last closed tab Ctrl +Left Click, or Middle Click

Open clicked link in a new background tab Shift +Left Click

Open clicked link in a new browser window Ctrl + Shift +Left Click

Open clicked link in a new tab, and set focus to it Reading Space

Scroll down Shift + Space

Scroll up Home

Go to top of page End

Go to bottom of page F11

Toggle full page mode Ctrl + + , or Ctrl +Mousewheel down

Zoom page larger Ctrl + - , or Ctrl +Mousewheel up

Zoom page smaller Ctrl + 0

Set to default zoom Bookmarks Ctrl + D

Add current site to bookmarks Ctrl + H

Open browsing history Ctrl + J

Open download history Search Ctrl + E , or Ctrl + K

Set focus to search box Alt + Enter

Perform search in new tab F3 , or Ctrl + F

In-page search F3

Scroll to next in-page search item Ctrl + F3

Scroll to previous in-page search item Developer Ctrl + U

View source of current page F12

Developer tools Ctrl + Shift + Del

Delete browsing history

While it's not a keyboard shortcut per se, also note that left-click-and-hold on the forward and back buttons will show a list of the last (n) pages to select from, if you want to go forward or back more than a single page at once. This comes in handy at least once a week for me.

It's good to see browser developers standardizing on at least a few common keyboard shortcuts rather than making up their own.