Well there is always uncanny eyes.
This originally was an Adafruit sketch for the Teensy 3.2 using the 128x128 TFT/OLED displays. The author (Phil Burgess / Paint Your Dragon) used advanced display optimization techniques only on the Teensy 3.x of SPI FIFO/DMA support. Adafruit also ported the code to its M0 board the Hallowing M0 Express (ARM M0 processor with a single 128x128 display), using the DMA SPI support on the Adafruit ARM M0 chips:
Then the author rewrote the code for Raspberry Pi:
This year, he rewrote it again for the new Monster M4SK (two eyes) and Hallowing M4 Express (one eye) for the new 240x240 displays. He used the native DMA support on the Adafruit ARM M4 systems and the built-in flash memory to hold the eyes, so I'm not sure whether you could easily port the code over to Teensy:
During the late T4 beta cycle, I asked whether we could run the original program on the T4, given the SPI stuff had changed under the covers, and whether there was hope for getting the 240x240 displays running. KurtE, Mjs513, and Defragster took it up and ran with it, and they tweaked the original program so it would run on the T4 and support the 240x240 displays, including the cheap displays with no CS pin.
While the code for the ST7735_t3 library that they were working on is in the 1.48 release, unfortunately the uncanny eyes example program was not in the 1.48 release. You can grab it from:
In terms of displays, I've been using the Adafruit 1.3" display, but you could also use the larger 1.54" Adafruit display, or the various 3rd party displays that use the ST7789 chipset and have through pin support:
Particularly for the no-name displays, check out the ship time, since some of these ship from China, and it is 11 days to Halloween.
I believe when you use this, you need to use the display bus exclusively for the display, particularly if you use the displays without a CS pin. This means you would not be able to use either the micro SD card or the optional flash memory on the audio shield. Alternatively, you could put the display on the 2nd or 3rd SPI bus. If you want two eyes, you will need to use two SPI buses. If you want to use the SPI bus for the audio shield, you will need to connect the displays to the 2nd and 3rd SPI buses.
To get to the 2nd SPI bus, you will need to bring out pins 26 and 27 from underneath the Teensy. To get to the third SPI bus, you will need to bring out pins 35, and 37 from underneath the Teensy. Pins 35 and 37 are harder to do, because this solder pad is 1mm instead of the 2.54mm (0.1") and is made for bringing out the micro SD card. There are various breakout boards floating around, but again, it likely is too late to get anything fabbed from OSH park. Perhaps somebody has extra stock if you needed it ASAP.