If you are in search of agencies that are working in Oslo, then here I will list down the names of few agencies currently working in Oslo.
Loyalty
Hyper
Bleed
Oslo Digital
ANTI
Bold
Unfold
Good Morning Naug
Netron
Spoon
Work
Feed
Involve
Uppercase
Envision Ecommerce

Many more agencies like these are working in different areas.

https://digitalagencynetwork.com/agencies/oslo/