TheSeth

for a fully-featured DAW there's Ardour https://ardour.org/ which supports lots of the proprietary plugins (VST etc.)

There's also this architecture proposal by the maintainer of iPXE: https://github.com/ipxe/cx

it's just an gateway to enable standard clients to talk to an Exchange server

I've used DavMail to stay outlook-free for the last year or so. It seems quite dependable, subject to Exchange's regular brokenness. Mean-spirited windows admins do sometimes lock out the URLs it uses, though.