Hi Damon,
There's a wiki site that the brew forum put together of beers that they managed to culture the yeast from and some that didn't work either because they are pasteurized or use a different bottling yeast to the fermenting yeast.
Mostly German and Belgian but some international ones in there too.
https://hobbybrauer.de/forum/wiki/doku.php/hefestripping
The only ones I have done myself were Bolton Uhr Alt and Schneider Weizen.
They were easy and have a load of original yeast in the bottle especially Schneider.
As for online shops, I find there is no one-stop shop that beats them all.
Braumarkt and Brouwland are where I have been shopping lately too but really depends on what you are wanting to buy.
You can't beat Brouwland prices for some of Halltauer Hops, 2 euro for 100 grams or 16 euro for a kilo.
Amihopfen is another one with a wide range of products with not the cheapest but OK prices.
There are other shops that offer better prices on more exotic hops, especially if you buy in bulk.
It's really worth shopping around as the prices vary a lot.
This site here makes it possible to check the prices on about 25 different shops related to brewing including Pinta in Italy and others around Europe.
Which works out cheaper than German shops if you make a bigger order.
https://brauen.online/zutatensuche/
The search doesn't work perfectly for all shops but at least it's a list of other shops that you can check their websites.
Resch hops has a good selection of hops at decent prices and free shipping on orders over 30 euro.
They also have weyermann malts and some dry yeasts and DME.
My last order was actually from Ireland, the Homebrew Company.
http://www.thehomebrewcompany.ie
They had some hops, British and American malts (Honey Malt, Naked Golden oats) cheaper than or that I couldn't get from the German shops.
Plus the bulk hops (Kg) prices are good and they often have a 10% discount.
So the savings more than covered the extra shipping costs.
Just make sure you register on the .ie and not the .co.uk website or else they will charge you British sterling instead of euros.