Finding the right travel plug Thailand is not that hard.
Thailand has the same supply voltage as Germany (220v 50Hz) so many hotels and smaller plants european compliant sockets. One can its connector so usually easily use without accessories.
Who wants to play it safe, may be on Amazon Order or E-Bay suitable adapter plugs for about 1-3 €.
Although we had wrapped Travel Power Plug Adapter, this however never needed.
Even in the local Thai Regions, you can easily use the German plug for sockets without a travel adapter.