I2C is used at run time in 10 crates (of which 8 optionally). It is a direct run-time dependency in 4 crates.

Depender (with downloads and own rev deps) I2C version
2.5K 4 i2c-linux optional ^0.1.0
500 1 ddc-i2c ^0.1
i2c-i2cdev ^0.1.0
380 2 nvapi optional ^0.1.0