Great list, thanks for sharing!
Animal Advocacy Careers also has a Job Board.
If you don't mind me plugging my own org, Vegan Hacktivists specializes in building software for other animal advocacy/protection orgs, along with offering tech, design and advisory services, all for free.
Will keep an eye out on this thread, would love to learn about other organizations using technology as a catalyst for good!
I would argue that the majority of software products are aiming at making a positive impact, and my guess would be that the products that have the biggest impact are wholly unrelated to EA. Having said that, here are a few that seem in line with the spirit of the question: