Welcome to what I hope will become an interesting series of threads regarding various naval aspects of ww2.
To start off, let's focus on the famous pocket battleships. Al lot of the discussion I've seen so far was about what the Germans could have built instead. However, this isn't about that - instead, let's suppose Weimar Germany never builds them, or any other 10,000 ton ship as permitted by Versailles in the first place! There was considerable opposition to their construction OTL from the left, with the communists proposing a referendum be carried out on whether to build them. Assume the SPD agrees, and "No" wins out at the ballot. History proceeds more or less as OTL - Hitler looses the presidency to Hindenburg, NSDAP does great in parliamentary elections, and the old fart appoints Hitler as Chancellor.
Hindenburg pledges to respect the results of the referendum, and thus Hitler can only start contemplating starting construction of any capital ships after the old man croaks, in late summer - early autumn 1934.
In theory, we could still get all of the other ships minus the 3 Deutschland-class, possibly with a bunch of slightly modernized pre-dreadnoughts on top. But would we? And what else would change?