One of my favorite “underdocumented” features of Firefox for Android is the ability to add custom search engines to your “Awesome Screen“. Almost any website with a search form can become a search engine. Just long-press in the search form’s text box and Firefox will display a popup menu with an “Add Search Engine” command:

For example, BoardGameGeek is a popular gaming website with reviews of many, many games. I added BoardGameGeek’s search form to my Awesome Screen so I can quickly look up reviews when I’m shopping at my friendly local game store: