I could not find information about it on the Internet, I would be happy for a link from ebay/amazon or type of diameter required. prius 2010
The Toyota part number for the metal gaskets used for the transaxle filler and drain plugs, for all Prius cars, is 90430-18008. In some countries, Toyota dealers may sell 90430-A0003, 90430-C0011, 90430-T0011, 90430-T0021, or 90430-W0001 instead. I have some examples of 90430-18008 here. They look like the photos of the 90430-A0003 on parts.toyota.com and the 90430-18008 in @dolj's posting. The approximate dimensions are: outside diameter 24.0 mm, inside diameter 18.2 mm, and thickness 2.00 mm. I have no recommendations for third-party equivalents.
Amazon link from when I purchased some a few years ago. Not sure if link will work from where you are located. amazon
Just to pile-on: My approach, as with a lot of such purchases, is to just go to parts department of local dealership, let them sort it out. But maybe where you are that’s not practical?