Safe silver electroplating solutions
I've never tried to grow big crystals or anything, but we commonly use 30 mM silver nitrate in 1 M $\ce{NH4OH}$ for electrodepositing silver onto metal (usually gold) electrodes.
If you don't care what kind of surface finish you end up with, it will work, but it makes a fairly rough film that can be somewhat easily removed with abrasion.
The tricky part is trying to get very smooth and adherent films.
It seems that there are still not any good replacements for electroplating from cyanide-containing solutions, for decorative or engineering purposes where the deposit will be subject to wear or has to look nice.