Deck is described as 'There's is always one more thing to learn "There's is always one more thing to learn" so why not learn in more better way possible' and is an app in the Education & Reference category. There are more than 100 alternatives to Deck for a variety of platforms, including Online / Web-based, Android, iPhone, iPad and Windows. The best alternative is Anki, which is both free and Open Source. Other great apps like Deck are AnkiDroid (Free, Open Source), RemNote (Freemium), Mochi (Freemium) and Quizlet (Freemium).
Anki is a program which makes remembering things easy. Because it is a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
RemNote is the note-taking tool that gives you memory superpowers. It automatically generates flashcards from your notes and figures out the optimal time to practice each flashcard so you don't forget what you've learned.
Learning with Texts (LWT) is a free tool for Language Learning by reading & listening to texts, saving & reviewing vocab. Prerequisites are an installed LAMP/WAMP/MAMP (local web server & database) software and a modern web browser.
Vocabulary.com is the easiest, most intelligent way to improve your vocabulary. It combines an adaptive learning system (The Challenge) with the world’s fastest dictionary (The Dictionary) so that you can more quickly and more efficiently learn words.
Mnemosyne (named for the Greek goddess of memory, Mnemosyne) is spaced repetition software developed from 2003 until the present. The software is similar to SuperMemo, commercial software developed by Piotr Wozniak.