This is the best CocoaPods library that I use for Swift 4!
Realm is a mobile database that runs directly inside phones, tablets or wearables.
This repository holds the source code for the iOS, macOS, tvOS & watchOS versions of Realm Swift & Realm Objective-C.
CocoaPods : pod 'RealmSwift'
Alamofire is an HTTP networking library written in Swift.
For example you can load images to ImageViews from your server.
CocoaPods : pod 'Alamofire'
The better way to deal with JSON data in Swift
You can use Alamofire and SwiftyJSON to use API’s easely.
CocoaPods : pod 'SwiftyJSON'
This is a library for AutoLayout. You can make Auto Layout easy on both iOS and OS X.
This video was very good Tutorial.
CocoaPods : pod 'SnapKit', '~> 4.0.0'