gulp-autoprefixer -- CSS vendor prefixes
    gulp-concat -- concatenates multiple files into one
    gulp-cssmin -- CSS minifier
    gulp-imagemin -- image optimizer/minifier
    gulp-rename -- renames files produced by other streams
    gulp-ruby-sass -- transpiles SASS to CSS
    gulp-template -- interpolates some variables, e.g. environment settings or external dependency URLs, into a file (basically lodash's .template )
    gulp-typescript -- transpiles TypeScript to JS
    gulp-uglify -- JS minifier
    gulp-util -- provides things like access to environment variables, console.log replacement, Gulp-specific throwable errors
    gulp-watch -- automatically recompiles when source files change
    gulp.spritesmith -- converts images to CSS sprites