Another such umbrella organization is Software in the Public Interest (SPI). Some of the more notable projects they sponsor include Arch Linux, Debian, FFmpeg, LibreOffice, OpenSSL, OpenZFS, PostgreSQL, and systemd.
Homepage: https://www.spi-inc.org/
If you care about Python, you could support the Python Foundation, and/or hire or sponsor some Python developers. If you care about Rust, support the Rust Foundation, and/or hire or sponsor some Rust developers. If you care about Reproducible Builds, or QEMU, or Git, or Inkscape, or the future of FOSS licensing, or various other projects (https://sfconservancy.org/projects/current/), support Software Freedom Conservancy.
If you care about a smaller project, and they don't have a means of sponsorship, you could encourage them to accept sponsorship via some means, or join some fiscal sponsor umbrella like Conservancy.