- [BitKey](https://bitkey.io) Live USB for airgapped transactions and Bitcoin swiss army knife
- [Pycoin](https://github.com/richardkiss/pycoin) Python-based Bitcoin and alt-coin utility library.
- [sx](https://github.com/spesmilo/sx/) sx - command line Bitcoin to empower the sysadmin
- [bx](https://github.com/libbitcoin/libbitcoin-explorer) Bitcoin Command Line Tool
- [txwatcher](https://github.com/tsileo/txwatcher)A little Python utility that lets you monitor Bitcoin addresses through Blockchain Websocket API and perform custom callbacks.
- [hellobitcoin](https://github.com/prettymuchbryce/hellobitcoin) A collection of simple programs which can generate bitcoin wallets, create and sign transactions, and send transactions over the bitcoin network.
- [btctxstore](https://github.com/F483/btctxstore) simple library to store/retrieve information in bitcoin transactions using OP_RETURN
- [pybitcointools](https://github.com/vbuterin/pybitcointools) Python library for Bitcoin signatures and transactions from Vitalik Buterin. Project discontinued.
- [pycoin](https://github.com/richardkiss/pycoin) Python library for Bitcoin keys, signatures, transactions. Includes full VM implementation and tools for manipulating keys (ku) and transactions (tx).
- [bitcoin_tools](https://github.com/sr-gi/bitcoin_tools) Python library for building and analyzing transactions and scripts (both standard and custom). Comes along with a UTXO set analysis tool. Includes several examples and exhaustive documentation.
- [XChange](https://github.com/timmolter/XChange) Library that provides a simple and consistent API for interacting with 50+ Bitcoin currency exchanges.
- [NBitcoin](https://github.com/MetacoSA/NBitcoin)Comprehensive Bitcoin library for the .NET framework.
- [BitcoinLib](https://github.com/GeorgeKimionis/BitcoinLib) The most complete, up-to-date, battle-tested .net Library and RPC Wrapper for Bitcoin and Altcoins in C#.
- [QBitNinja](https://github.com/MetacoSA/QBitNinja) An Open Source and powerful blockchain API
- [WebBTC](http://dumps.webbtc.com/bitcoin/) These are postgres database dumps of the bitcoin-ruby-blockchain database generated by webbtc.com.
- [BitcoinDatabaseGenerator](https://github.com/ladimolnar/BitcoinDatabaseGenerator) A high performance data transfer tool that can be used to copy data from Bitcoin Core blockchain files to a SQL Server database
- [Blockparser+SQL](https://github.com/mcdee/blockparser) Fast, quick and dirty bitcoin blockchain parser
- [BitcoinABE](https://github.com/bitcoin-abe/bitcoin-abe) Abe: block browser for Bitcoin and similar currencies
- [NBitcoin.Indexer](https://github.com/MetacoSA/NBitcoin.Indexer) Scalable and fault-tolerant block chain indexer for Azure cloud platform.