Yep, I can also never remember the useful ls command combos so I'm adding them all here so I can check in and grab them.
List files by modified date in reverse order (last edited on last line, the most useful way to do it!)
ls -ltr
List all directories in current directory
ls -d */
List everything on a new line
ls -1
Show hidden files
ls -a
Show files recursively - not massively useful unless piped to something else.
ls -R
Show list of files including inode value, useful when you want to delete those files with crappy filenames.
ls -li