Should I add TruncatedPrior here - https://github.com/bambinos/bambi/tree/main/bambi?

I think this should do.
This sample function truncates a normal distribution. You can adapt it to other distributions as needed:)

I think it should go here - https://github.com/bambinos/bambi/tree/main/bambi/priors ; and I think you can take inspiration from the Prior and PriorScaler classes. Hope that helps!

So users can truncate any distribution

Edit after seeing #875

We want to give users the option to truncate any prior distribution. Under the hood, this should be done via pymc.Truncated().

I still don't know what this would look like, but I can throw the following ideas.

Option 1

bmb.Prior("Normal", mu=0, sigma=1, transform=pm.Truncated, transform_kwargs={"lower": -1})

Option 2

bmb.Prior("Normal", mu=0, sigma=1, transform=lambda x: pm.Truncated(x, lower=-1))

Option 3

bmb.Truncated(bmb.Prior("Normal", mu=0, sigma=1), lower=-1)

Option 4

bmb.Transform(bmb.Prior("Normal", mu=0, sigma=1), pm.Truncated, {"lower": -1})
I think I prefer Option 3, but still I like how general Option 4 can be.

option 3 i guess is better as it seems simple and easy to implement then other ones, let me know your review then i'll add option 3 in the priors;)
Also should I extend the PriorScaler class to include the option for creating truncated priors?