russian transit plates can be had rather easy - they are placed on a car that leaves the russian federation (or just came in) for export or whatever, and once the car gets permanent local plates, the transit plates are discarded... that is how i ended up with my russian transit plates...

in costa rica they would not allow me to drive a car until permanent plates were installed onto the car, but they would allow US plates to be placed onto the car, which i used my PA vanity plate with my wife's name on it, and the locals were very intrigued to see letters on a plate, let alone to spell an actual name...lol... their plates are 100% numerical, which is stupid, at one point they will run out of space on the plate...

but, no transit plates in CR...