avr11: building an SPI SRAM shield for an Arduino Mega | Dave Cheney
diymore ESP32 WROVER 4MB SPI Flash 8MB RAM 0.96" OLED USB to TTL Serial CP2104 Five Way Button 18650 Battery Holder for Arduino|Integrated Circuits| - AliExpress
Arduino SPI RAM II
Adafruit SPI Non-Volatile FRAM Breakout - 64Kbit / 8KByte : ID 1897 : $5.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Interface an SRAM Bus to Your Arduino : 3 Steps - Instructables
SPI RAM Shield for Arduino from FemtoCow on Tindie
23K256 256k SPI Bus Serial SRAM - Datasheet
23A256 SPI RAM with Arduino Mega - Networking, Protocols, and Devices - Arduino Forum