There are vector logos for five of the sites: https://stackoverflow.com/company/logos.
I was wondering if there were also vector logos for the other sites that are available for download? (I am looking, in particular, for Mathematics, but ideally I'd like them all!)
Edit: Thanks to IBUG's answer, I've gotten a few of them and can share these few logos in SVG and PDF format - Google Drive.
Unfortunately I don't know any programming and this takes me a bit of work. Hopefully someone else who knows better can easily get them all and share all of them with everybody.