The idea of exploring the oceans sounds very interesting to me. Mainly because of the fact they cover 2/3rds of the planet and they are huge bodies about which we know very little. One idea was to use an aquatic drone but it can also be done using a weather balloon or a DJI.
Space and seeing the planet from a very high altitude. About the height of 10-15km up to about 25 km. 100,00 ft. Using weather balloon.
Use a telescopic drone to film the milky way. From a high altitude.