Yes, the OLED display used for OpenSprinkler is 0.96″ I2C SSD1306. You can find it on many websites, including Aliexpress, on which many vendors sell it for just a couple of dollars with shipping included. Just watch out the pin ordering: it should be GND-VCC-SCL-SDA, which is the most common type. I am, however, aware of a couple of new models which use VCC-GND-SCL-SDA ordering, and that is incompatible. So check out their product pictures before burying.