Hello! I've been investigating what items are possible to get in "Classic skyblock" and I found that it's possible to get more Lava and Obsidian in MineCraft Without Cheats or Modifications

First thing you will need is a villager which you can get by curing. to cure it you'll need a witch and a golden apple
to get the gold for the golden apple you must smelt golden armor you obtain from mobs.

After curing your zombie villager you must make him a mason which has a chance of selling Dripstone.


You must buy a dripstone, hang it on a block and above the block you hang it place the laver bucket you already have. after that place a cauldron under the dripstone and wait it may take a few hours to fill with lava which you can then use!