What do you mean with new partners? As far as I know they are currently partnering with VISA. Are they looking to partner with Mastercard? Other big card providers doe not exist, except American Express, but it does not partner is such fields of business.
Since Uquid is currently not issuing new cards, do someone have experience with an alternative provider? I am urgently looking for a good service for a Bitcoin debit card.
A card provider is not the same as a card network. A provider is the one with the card licensing and partnerships with Visa/Mastercard already set up. A card network such as Visa or Mastercard is one that already has all transaction endpoints set up for the user. The provider simply partners up with Visa/Mastercard/whomever in order to be able to issue cards to people. Companies and organizations such as UQUID then make deals/contracts with providers and agree to follow their rules and guidelines for issuing cards under different customization options for their respective clients. Furthermore, the actual providers don't usually hold the money in the accounts, as the end companies themselves usually have a system for that. If you look at the API for a provider you will be able to see what UQUID and other similar companies have access to and have to manage on their end. A lot of it is actually out of their control and depends on the providers.