Emmaüs has a Linux PC team, they even have a light weight distribition derived from Ubuntu to help repurpose old hardware:
https://en.wikipedia.org/wiki/Emmabuntüs
No idea if Emmaüs is is anywhere outside of France though...
Nearest I can find is Stifter-helfen.de who are associated with Tech soup in the US but from what I can see they are interested in donations of recent complete pcs from corporate partners, not single donations and not the 20 year old cases that I will be throwing out.
Translated
"PDF product catalog: IT donations and special conditions
As of: April 8, 2019 On the IT portal
www.stifter-helfen.de clubs, foundations, gGmbHs and other non-profit organizations can find IT donations from various IT and Internet companies as well as special conditions and know-how about modern technologies. Stifter-helfen.de is an offer from the Haus des Stiftens gemeinnützige GmbH in partnership with the American non-profit organization TechSoup.Availability of the products In our PDF product catalog we give you an overview of the available products in our IT Donation programs and the products for which special conditions apply. In the area of special conditions, non-profits find discounted IT products, such as devices from the program, hardware as new at cost price, or discount programs from IT companies. The products are sorted alphabetically by company name into the two areas of IT donations and special conditions. Since the extensive product range is updated several times a month, deviations from the products actually available online are possible. The product catalog is a non-binding offer and applies according to the eligibility criteria of the individual IT partners, as long as stocks last. Decisive for the availability of products is always our homepage
www.stifter-helfen.de. Management fee To cover the costs of operating and developing Stifter-helfen.de, a small administration fee per product is due. The administration fee is net and is calculated plus 19% VAT per item. Exception is 'hardware like new'. There is the price including VAT indicated. You will find the administration fee in the product catalog for the respective products and of course online. Since this is constantly changing due to exchange rate adjustments, the information on our homepage is always crucial. On
www.stifter-helfen.de you will find all information on the available products and the individual eligibility criteria of the IT partners. Additionally, nonprofit organizations can register on the site to receive IT donations and special rates. If you have any questions, please do not hesitate to contact our staff at
info@stifter-helfen.net or 02241/146408 - 0. Your service team from Stifter-helfen.de - IT for non-profitsFor registration formula"
Any one else in Germany have any suggestions, know any charitable donation sites?