Unfortunately, not a lot of websites these days have a lot of resources for songs that are pre-60’s or not particularly popular. That’s one of the downsides of the Internet: popular things are widely available (sometimes too much so) but more obscure things are made even more obscure.
Instead of trying to find tabs, look for books of sheet music. A little searching on music websites (or, even better, in music stores with knowledgeable staff) will probably yield some decent results. You can find a huge amount of stuff on the internet, but there are still some things that you have to go out and find the old-fashioned way.