4x4 maps

Do you mean to load into the Prado's nav system? If so, I doubt any are available unless the original system has been replaced with an after market one that can run Ozi Explorer or some such. In which case there are many digital maps available, some of the best being the EOTopo suite. There are many others, often available on CD or download and you transfer them to a suitable SD card.

My experience is with EOTopo, EO Traveller and buckets of maps on Ozi Explorer. Others will have other options for you.

Cheers

https://oziexplorer4.com/eng/aussie_au.html
Overall found them surprisingly good.
Used them fairly extensively..

There's quite a bit of discussion about the Prado maps issue on the Pradopoint website LD and although it's been a while since I read threads on the topic, from memory people have used a variety of workarounds to try and get Toyota's navigation system to recognise other maps - with almost zero success.

Seems there are two practical solutions:
(1) Replace the Toyota head unit (not that difficult to DIY) with a new-tech Android head unit. Prices vary, but say ~$600. These will run pretty much everything you want. You won't be limited to Toyota's outdated maps and can source detailed maps from a variety of suppliers (paid and free maps available). You may also want to consider a mapping program to manage your map data and trips. Exploroz has lots of info on that topic.
(2) Run a second, independent, display such as an Ipad/tablet with your maps, mapping program and GPS installed. The tablet can also be used for internet, email etc.