Naturally it's impossible to add in this section all doublebass orchestral excerpts. These are some examples and during the time I will try to add the ones more important expecially when you have to do an audition. 

http://www.operaroma.it/artisti/audizioni_e_concorsi

http://odeo.com/channels/115633

You will need of the sheet music (papers) but it the better way to practice with doublebass excerpts.

http://66.70.247.75/cgi-bin/closedShop/Item.pl?category=doublebass&action=ShowCategory

https://www.eble.com/store/index.php?manufacturers_id=2975%3DOrchestral+Parts&sort=2a&filter_id=159&osCsid=be79a082da9121bc8b5147e780085e4c

https://www.eble.com/store/index.php?manufacturers_id=1935=Orchestral%20Excerpts

https://libwebspace.library.cmu.edu:4430/arts/music/musibass.html#Orch

http://www.tfront.com/product.php?pid=110814&qstring=Double%20Bass&qformat=MU&lm1=120&nf=733

http://shop5.mailordercentral.com/lemurmusic/Etudes--Excerpts/products/65/0/3

http://www.music44.com/X/product/49007580-H

When we talk about "orchestral excerpts for double bass", today we know that there are hundreds of books or collections that cover the symphony and opera. Now also supply the CD I think midi through which you can study by following the sound of a piano or another instrument. You can vary the speed and so on.
But nobody will tell you if your study has done well conducted. You will only run at an impressive speed a solo from "Pulcinella" , well-tuned. But if in your life you've never heard live or on a CD 's entire symphony, you will not be ever clearer vision of your interpretation. So, imho, is always better to listen to what we should do and not blindly trust the Midi files, sometimes very misleading.

Let's listen to what we have to play ... then will study in another dimension. IMHO

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