[matsemann]

I think it used to be F4 or F6 or something for Explorer. I also used to use F6 in firefox, took some time re-learning Ctrl+L when that changed. (Edit: F6 still works, but it cycles elements (one which is the address bar) so ctrl+l is better)

[efreak]

Alt-D. I have this shortcut so well ingrained in my head that duckduckgo is nearly broken for me. They have a single shortcut alt+d that searches for results from the same domain. This is enabled by default, so if you use ddg as your default, it can't be disabled for private browsing mode (I use private browsing mode to avoid opening a full browser session with extensions and saved tabs/windows).

Anyone who captures keyboard shortcuts in the browser using function keys like Ctrl/alt (outside of applications like games, rich text entry, and software like Google apps) needs to rethink the way their website works. This includes squarespace(?) intercepting ESC, and websites that do server-side searching. Worse yet, when I press Ctrl+f, I want to search the current page for a word, not search your website. (I saw this recently, and it was only made worse because you couldn't actually dismiss the search overlay without reloading the page)