The best alternatives to Gitify are Explorer for GitHub, Neat, and GitPigeon. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Gitify?
Agree.com— The Best E-Signature Tool for Getting Paid (Fast)
Neat puts GitHub notifications in your menubar. It empowers high-performing teams to review, merge, and ship code with ease. Users can preview, triage, and jump to the browser without switching tabs. Available for free on macOS.