Not a program, but being very familiar with the keyboard shortcuts in SublimeText has saved me countless hours of dev time.

Things like Ctrl-D to highlight multiple instances of a word, plus the ability to put on Caps checking in the search bar first so you're only highlighting correctly capitalized versions. Make the same change in multiple locations. Saves so much time.

Knowing how to highlight a letter, a word, a line at a time.

Ctrl-shift-down to make your cursor span multiple lines at the same point, and have copy/paste respect the copied text from the respective lines.

So many things add up to hours upon hours of time saved, and frustration avoided.