quit.blend is a copy of the latest project at the moment when you quit blender.If you where to use "Recover Last Session" that would be the file that gets used. The quit.blend file works even on projects that where never saved, but where active when you closed blender.
Note that if blender crashes, or the blender app is force-closed (interrupting the process) this file will not be updated.
The rest are the previous version of other files you where working on, and were created as auto-save versions most likely (it really depends on how you set up your preferences).
If you want to reclaim .0001% of your hard drive space you can delete all of these files and blender would still work. None of those files are necessary for blender's operation.
As a rule, nothing that is precious to you, or that you'd regret loosing should ever be in the tmp folder. Depending on the operating system sometimes those files get cleared away automatically on boot.
The rest of the folders are not blender related and might contain information used by open apps or ongoing processes... I don't know what would happen if they get deleted... but that is not a question for the blender.stackexchange...