TiddlyWiki in many ways is the best predecessor to Obsidian, in that it follows many of the same priorities and tradeoffs.

I was a big user of TiddlyWiki but Obsidian has so many UI quality of life improvements, and the plugin ecosystem is evolving at such a rapid pace that I decided to jump ship.

I wrote a guide on my migration process: https://forum.obsidian.md/t/import-from-tiddlywiki-5-to-obsi...