Returning to natural colour

[HighOnStilts]

Good evening all just looking for some advice/tips.

Have been dying my hair black for the past few years, I've always used a generic box dye (nutrisse, nice 'n' easy, clairol)
I'm wanting to now grow my natural colour out as I'm due in March and frankly I just can't be bothered with it anymore. I just wanted to know if there are any products I could use to lets say, speed the process along. My hair is pretty long and I have it cut regularly. Also my natural colour is mousey brown.

Thanks in advance! 🙂