SSD1306 is a bit in the middle. It's technically a 128x64 monochrome bitmapped display, but it's organized as eight 128x8 "rows", with each byte representing a single 1x8 group of pixels. That organization really favors being treated as either four or eight lines of text - trying to use it as a generic bitmap display gets awkward, because it's only addressable at the level of those 1x8 groups.

ST7735 is more of a standard (color) bitmap display.