Seriously theres just too many to list but a starter would be crags in the Llanberis Pass (Dinas Mot/Dina Cromlech etc), the sea cliffs of Gogarth, tremadog- Theres just so much. To get the most out of it tho you would need to commit to bringing a small rack (1 set of nuts and cams) and a rope. Just pick the selected guide book when you get here.
The bouldering is awesome tho and worth the trip alone. Check out: