Sketch was taking up around 130GB in my DocumentRevisions-V100 folder. I got this from Sketch support, hopefully it helps others.

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You can delete the revisions folder in order to free up that space (versions). Please download the following app:

http://www.titanium.free.fr/onyx.html

It’s one of the safest to delete the revisions folder without creating other issues.

In Sketch 3.4 we’ve added an in-app feature to disable the auto-save, please check Sketch preferences.

We don’t recommend that you disable it but it’s the only option you have to stop creating all those versions of Sketch docs in that folder.