You can find Unown in the Solaceon Ruins and that is the only Pokemon there so you shouldn't have a hard time finding one.
Unknowns are in the soleceon ruins.
the simble pokemon, unknown.
The Unown are in the Solaceon Ruins.
you can catch a lot of unknown Pokemon A-Z
There are 26 but since there are the ! and ? unknown 28 total
To get a Venusaur on Pokemon Diamond you have to get the National Pokedex and look for its area, if it's unknown then I don't know what to do.
right of solaceon town
turn back cave
Solceon ruins.
in the Solaceon Ruins.
You can find them in solaceon ruins
#114 is unknown. its found in the soleancean ruins
Unknown(sorry about my spelling) Letter A is the rarest Unknown in all games. You are more likely to find a shiny Pokemon then Unknown A but if you are dedicated then go for it but prepare for frustration.