Potential additions
from search results User:Ceyockey (talk to me) 
 Ocean bottom observatory
 appearing in Loihi Seamount#Activity
 Obo River
 appearing in Thudaka Range and Ruby Range (Sifton Ranges) and Thudaka Peak
 O.b.O.
 appearing in Igor Dymkov
 Obo, Papua New Guinea
 appearing in Obo Airport (Papua New Guinea)