VTK has had support for visualizing arbitrary-order Lagrange elements for a while now, but there aren't many resources out there (as far as I know) facilitating their use. Notably, these elements rely on a particular "onion-like" node ordering which many solvers (including mine) don't use by default. This means that people developing high-order solvers have to generate specific sets of visualization nodes which conform to such an ordering in order to use these VTK element types.
What I would really like is some way of generating unisolvent sets of nodes on reference (e.g. right-angled) triangles, tetrahedra, quadrilaterals, and hexahedra for a given polynomial degree, with the ordering given according to VTK's convention. Does such a tool exist? Even a database of hard-coded coordinates for different polynomial degrees (say, up to 10) would save me, and probably many others, a lot of time.