Models

Donation-based - large donors and/or recurring small donations
Bounties - for fixing bugs / implementing feature requests
Grant Funding
Government Funding
Paid Services
Commercial / proprietary use pays

Case Studies

SSB – Microgranting -- story to tell along the way
Guifi/Benefitoria & Patreon – sustainable crowdfunding

Projects

Code for X (e.g. codefor.ca)
SourceCred is a system for creating reputation networks for open-source projects, and give a sense of recognition for and ownership of contributions
Open Collective
Bcoin is a family of full node implementations. The project started as the back-end bitcoin implementation for Purse. Today it's one of 3 fullnode implementations running in production for Bitcoin. Bcoin forks include bcash (BCH), lcoin (LTC), and hsd (HNS).

Orgs / Foundations

Ford Foundation
Shuttleworth Foundation
Knight Foundation
Linux Foundation
Open Culture Foundation (ocf.tw who distribute small grants for civic tech community in Taiwan g0v)

Research / Works Cited

Nadia Eghbal's lemonade stand of funding models for open source and also her report - Roads and Bridges: The Unseen Labor Behind Our Digital Infrastructure