We offer specialized e-Commerce web hosting services, which usually involves large catalogs, and this is especially true in the case of drop-shipping.
See our professional offers that have an adapted resource allocation for dropshipping  e-Commerce websites :
https://www.yoorshop.hosting/ssd-cloud-web-hosting-europe-france 

The list of suppliers could be very long, and this is of course one of the most important choices in this business model...
You will have to arm yourself with a patience of steel in order to analyze with whom to work, at what price, what to sell, and how .... Sell a niche product range is the most hopeful : rareness factor...

And if you speak English, you will widen strongly your spectrum of opportunities, this list is very basic, try google also by including the activity field you search for :

https://www.aliexpress.com
https://www.bigbuy.eu
https://www.chinavasion.com
https://service.alibaba.com/buyer/faq_detail/10580793.htm 
http://www.wholesalecentral.com
https://www.dropy.com 
http://www.inventorysource.com/prestashop-dropshipping/ 
https://www.wholesaleforum.com/discuss/wholesale-dropshipping-reviews-5043/

Prestashop is very popular for e-Commerce websites, you can install it with a few clicks with Softaculous.
Buy a prestashop template, and build your shop quite easily ...

The management of the catalog is an important aspect in the long term to manage stocks, prices and items, it can be automatic or manual.
Some providers will offer their own prestashop module /ex : it will synchronize almost everything.
There are also dropshipping modules:
Https://addons.prestashop.com/en/443-dropshipping 

You can also handle this manually:
https://support.yoorshop.hosting/knowledgebase/991/csv-import-for-catalog-prestashop-and-regenerating-thumbnails.html

If you need a webmaster:
https://support.yoorshop.hosting/knowledgebase/1130/Where-to-find-a-webmaster.html