There are several other platforms and cryptocurrencies in the blockchain space that share similarities with Gitcoin in terms of supporting open-source development and incentivizing contributions. Some of these platforms include:

1. Bountysource: Bountysource allows users to post bounties for open-source tasks or issues. Developers can claim these bounties by fixing the issues, providing a way for them to earn money for their contributions.
2. Bounty0x: Bounty0x is a decentralized bounty hunting platform that enables users to earn cryptocurrency by completing bounties and tasks. It connects bounty hunters with businesses and individuals who need specific tasks completed.
3. SourceCred: SourceCred is a decentralized platform that provides a way to quantify and reward value creation in open-source projects. It uses algorithms to measure contributions and distribute rewards accordingly.
4. Augur (REP): Augur is a decentralized prediction market platform built on the Ethereum blockchain. While not directly similar to Gitcoin, it demonstrates the concept of incentivizing specific behaviors through blockchain technology.
5. PAN (Pandeia): PAN is a cryptocurrency project focused on funding open-source software development. It aims to create a sustainable funding model for developers and projects in the open-source community.

Remember that each of these platforms has its unique features and focuses.