With #554 nearing merge-ability, I'd like to start tracking support for some new datatypes somewhere. That place is here.

datatypes to be added

• times Writing to H5AD fails if AnnData contains datetime64 objects #455
  • numpy date times
  • pandas date times
• nullable pandas arrays Support for nullable bool, int in dataframes #504

Potential additions/ possible experimental support

• Ragged arrays via awkard array first attempt to support awkward arrays #647 Storing sub-obs (variable length per observation data) #609
• Ranges
• Time deltas
• xarray.DataArrays