Since MODX 2.5.7 it's no longer possible, out of the box, to create .htaccess files. You might run into this when setting up a new MODX site with friendly URLs, where you get an error when renaming the shipped ht.access file to .htaccess. Luckily there's an easy way to get that back.
I've recently been working on a project with Formalicious where the client requested dynamically-filled select inputs. This is pretty straightforward to set up, as shown in this tutorial.