One of the artifacts found in Middle Earth: Shadow of Mordor is a Broken Staff, accompanied by this memory:
Funny thing, that. They told us their names, plenty of times. But we all forgot. To a man, we forgot. It was like they didn't want us remembering. After a while, they were just the two Istari, and sometimes, the big one and the little one.
Can't say how I can't remember. I remember the bigger one telling us stories of a Goblin city, of a man who could turn himself into a bear, of the time when… well, I guess it didn't matter too much to him that some of his stories needed some cleaning up, or would scare a dead man out of his grave.
When the bigger one left, he took his cane. But he left a walking stick behind, with all these little notches cut into it. He was keeping track of something, for sure.
Are they the Blue Istari? They could conceivably be Gandalf and Radagast (unless these two were established to be elsewhere). The Shadow of Mordor Wiki suggests these are Blue Istari. Does the canon have anything to say? All I recall from Unfinished Tales is that they went east.