The European Commission has prepared an unofficial list of all active substances under the evaluation programme, broken down by the product-type for which they are being evaluated. This list is updated regularly.
Read the unofficial list on the European Commission's website
If you need to see the official lists, start by checking Annex 2 to the review regulation (EC) No 1451/2007 to see which sub-stances/product-type combinations had been registered for the EU evaluation programme for existing active substances as of 2007.
You can read the Commission's Regulation on the European commision's website: (EC) No 1451/2007
You must then make sure that the application for evaluation of an active substance has not subsequently been withdrawn by the applicant or refused by the Commission. You can find an updated overview of the active substances from Annex 2 to the review regulation that have since been subject to a decision of “non-inclusion” in Annex I to the Directive.
Read more on the Commission's website