1. Coinbase - Coinbase is one of the most popular cryptocurrency apps in Newcastle, UK. It allows users to buy, sell, and store a variety of cryptocurrencies including Bitcoin, Ethereum, and Litecoin. The app has a user-friendly interface and is available for both iOS and Android devices.

2. Binance - Binance is another popular cryptocurrency app in Newcastle, UK. It offers a wide range of trading pairs and has low fees compared to other exchanges. The app also has a variety of features such as price alerts and advanced trading tools.

3. Kraken - Kraken is a well-established cryptocurrency exchange that offers a secure platform for buying, selling, and trading cryptocurrencies. The app provides access to a wide range of cryptocurrencies and has a reputation for being reliable and secure.

4. Coinomi - Coinomi is a popular cryptocurrency wallet that allows users to store multiple cryptocurrencies in one place. The app is known for its strong security features and user-friendly interface. Coinomi also supports a wide range of cryptocurrencies and tokens.

5. Trust Wallet - Trust Wallet is a mobile wallet app that supports a wide range of cryptocurrencies and tokens. The app is known for its ease of use and security features, making it a popular choice among cryptocurrency enthusiasts in Newcastle, UK.

Overall, these are some of the most popular cryptocurrency apps in Newcastle, UK based on the number of downloads and user reviews. Each app offers its own unique features and benefits, so it's important to choose the one that best fits your needs and preferences.