TortoiseGit has a great merge tool, but you must install the entire package in order to use it. Many other git tools allow the use of TortoiseGitMerge as their merge tool. These files allow you to use TortoiseGitMerge without having to install the rest of the TortoiseGit package.
Latest Release - v2.14.2.0
I extract the exe file and the dll file from the package: TortoiseGit-preview-2.14.2.0-20230603-c9c538c-64bit.msi, which is a preview version, but fixes one gui issue, and I think this version is the latest version which can run under Windows 7 64bit, see the discussion here: TortoiseGitMerge GUI elements overlap with Ribbon on Windows 7 (#3874) · Issues · TortoiseGit / TortoiseGit · GitLab,
You can download the packae here: https://github.com/asmwarrior/TortoiseGitMerge_Standalone/releases/download/2.14.2.0/TortoiseGitMerge-2.14.2.0.7z