I've tried a few solutions for macOS recently. Bitdefender and Kaspersky were rather yappy, especially about Windows malware in Mails you wouldn't care about on a Mac in the first place. Feels like they feel a need to beat their drum to justify the cost.
I'm currently running F-Secure's FS Protection beta, but I'm sure F-Secure SAFE would serve you well.
Official AV tests haven't given it great scores, but I like (and trust) it. I run my own tests which oftentimes contradict those from the labs, but it's up to you with just how much salt you take them. F-Secure also seems to be light and doesn't interfere with my work at all.
As for Linux, I personally don't think a specific solution is warranted, hence I can't recommend any. Brain.exe has served me well for years on that platform.