Protocol Buffers are Google's language-neutral, platform-neutral, extensible mechanism for serializing structured data. Protocol Buffers currently support generated code in Java, Python, Objective-C, and C++
Bolts is a collection of low-level libraries designed to make developing mobile apps easier. These libraries, originally created by Facebook and Parse, have been open sourced and made available to others without a mandatory Facebook developer or Parse affiliation. Bolts includes "tasks", which make organization of complex asynchronous code more manageable, and an implementation of the App Links Protocol, which helps link content in other apps.
Google utilities are several tools made available by Google to developers and other individuals to use on permission. These tools range from Google Sheets, Google Docs, Google Slides, and Google Maps, to name a few.
Naver is a collection of APIs including, Clover Platform, Papago, Naver Maps, and Naver Login. Navers APIs have multiple use cases including, voice technologies and services, translation, and location-based applications.
PINCache is a fast, thread safe, parallel object cache for iOS, tvOS, and OS X. It is a key/value store designed for temporary objects that are expensive to reproduce, such as downloaded data or the results of slow processing.
Zxing is a multi-format 1D/2D barcode image processing library. This opensource pluggin even though presently in development mode, still is a great option for developers. The pluggin is optimized with JRprofilerand implemented in Java, with ports to other languages
Reactive X is the swift implementation of the Reactive programming language. Reactive X (RX) is a generic abstraction of computation expressed through the Observable <Element> interface. It is a extension for .Net
Google iPhone Utilities are a set group of API's and other tools that offer iOSusers the opportunity to have teh Google experience. Google iPhone Utilities are open source with limitation based on application and usage.
Godzippa library is no longer being maintained as of iOS13+ and macOS 10.15+, as the Foundation provides equivalent functionality through APIs like compressed(using:) and decompressed(using:). Godzippa regardless is still available to developers and can easily be implemented via its repo.
Objection is a lightweight dependency injection framework for Objective-C for MacOS X and iOS. Objection was built to stay out of your way and alleviate the need to maintain a large XML container or manually construct objects.
DTFoundation is a collection of utility methods and category extensions presently being standardized on. DTFoundation is available in a Non-Attribution-License form for 75 Euros for not having to include the LICENSE text.