It has emerged that Evan Blass has posted images of four previously undisclosed Nokia phones. In spite of the fact that we have no idea what they're called (only model numbers), they do suggest a shift in the design aesthetic.
We'll start with the N150DL and N1530DL first. A rounded rectangle in the upper left corner of each device's camera bump clearly divides into two halves. Assuming they have the notch, these are probably mid-range phones. The fingerprint reader on the side suggests an LCD, and a 3.5 mm headphone jack is visible on the top. We can't read the label on the three-camera system.
HMD Global currently uses a circular camera bump on majority of their smartphones, including the Nokia N151DL. Due to the lack of a fingerprint reader, the large bottom bezel, and the fact that we only see one camera, this is most likely an entry-level device (opposite another notch).
Finally, the N152DL is most likely an Android Go Edition handset, which means it belongs to the C-series of smartphones. The C-series attempts to be as economical as possible, thus it's not in vain that its design is extremely similar to the C1 or C01 Plus.
These four Nokias haven't been announced, but we anticipate to see more specific leaks before then.