Where do still all the throwing vials are coming from - there are no gelatins to fight anymore since years? I was not here for some years a while ago, so I have might missed something in that time.

They come from the Gelatin Golem as loot drops, but only when we have a Gelly War. Sadly we don't know when the next one will be.

They hinted at a gel war for some time over the winter.