I have seen a few questions about the availability of a BASIC compiler for the Arduinos.
Great Cow BASIC is one that actually works and is available for free at https://sourceforge.net/projects/gcbasic/
I have used it with the Arduino UNO, but it has code to be able to compile for a number of other microcontrollers.
I have no attachment to the people who developed this. Just wanted to make you guys aware since there have been posts in the past asking about BASIC for the Arduino.