На подобии такого можно сделать
// libs to css
gulp.task('css', function () {
	return gulp.src([
		'node_modules/normalize.css/normalize.css',
		'node_modules/slick-carousel/slick/slick.css'
	])
		.pipe(concat('_libs.scss'))
		.pipe(gulp.dest('app/scss'))
		.pipe(browserSyns.reload({ stream: true }))
});
// js
gulp.task('js', function () {
	return gulp.src([
		'node_modules/slick-carousel/slick/slick.js'
	])
		.pipe(concat('libs.min.js'))
		.pipe(uglify())
		.pipe(gulp.dest('app/js'))
		.pipe(browserSyns.reload({ stream: true }))
});