Toddler short books

[SleepingStandingUp]

I have written some for my DS that other people tell me are good, but surely the market is too over saturated to ever be anything more than a personal collection of stories for ds?

I presume you mean picture books? The market is very competitive, but that's not a reason not to try. It just means you will probably have to keep working at it and write a number before you get published. You need a thick skin!
Also be aware that picture books are written to a very specific 32-page format, which means about 12 double page spreads and usually under 500 words.
Ann Linford Paul has written a brilliant book on writing picture books.