There is a number of options you have for display shields for the D1 Mini: there is the nice OLED shield, there is a shield with a single WS1228B neopixel, there is the #D1 Mini Matrix Shield I’m still working on. But there is no high-resolution color display you could just slap on it. This “shield” doesn’t really deserve the name, it’s just a simple breakout board that connects the ST7735 display module with the SPI pins of the D1 Mini, and adds a trim pot for brightness control.
To save some pins, the CS pin is hardwired to GND, and the A0 pin is connected to MISO. That means you can’t connect other SPI devices while this is in, but that’s a rare enough case for me to care. It uses four GPIOs total, from GPIO12 to GPIO15. The backlight is connected to the 5V supply (to not strain the on-board 3V3 regulator) through a trim pot, so you can adjust brightness.
I used alternating holes for the module’s header, so that with some luck you should be able to plug in the module directly, without soldering a female pin header there — that should also save some space.