What was the Rarest Unown Form you found?

[Morningstar]

Okay so some of you have probably attempted to catch the 28 formes of the Unown. As you get close to getting the complete set, you find the remaining pieces to be harder to get. So I ask of you, what was the form of Unown that you had the most trouble finding?

 

[GhostFingers]

In Sinnoh was the last place i went looking for Unown. IIRC the one i found last was Y, and i wanted two. (One of each so i could transfer the spares up to Gen V.) The last four i needed were Y M C B - yeah, just like the song only not quite.

 

[Berrenta]

My only experience with finding wild Unown is in AS in that Mirage Cave. Out of the dozens of Unown I found, I've yet to find the H.