Git merge tool to select either `--ours` or `--theirs`?

I’m pulling oF from upstream and need to choose lots of changes with both added, some of them are an straightforward --theirs keeping changes from oF. But there are some others in which I have added a function here and there.

Is there a tool, terminal or GUI, that allows me to interactively select merging hunks one by one? I’m on Windows btw.