There was also homu, which predated bors and also did more or less the exact same thing.
Does your thing have any features that differentiate it from what bors does?
Beyond that, there are a couple of things that I don't believe bors has.
A big one that I built for myself was the idea of supporting "working hours", i.e. only merge code during this timeframe.
For example, one company I worked for had some pretty flaky tests. Unfortunately, what would happen is we would have several PRs get reviewed and then use a tool like bors to enqueue them. Inevitably, some queued PR would have a failed check for this flaky test.
Fast forward to the weekend and a completely different developer would merge a hotfix into master. Unfortunately, a side effect would be that a tool like bors would try to merge the head commit into the PR with the flaky test, and now it passes! So it gets deployed at a random unexpected time, which isn't what we wanted.