! conda list | grep -E 'bokeh|holoviews|geoviews'
bokeh 2.2.3 py38h578d9bd_0 conda-forge geoviews 1.8.2 py_0 conda-forge geoviews-core 1.8.2 py_0 conda-forge holoviews 1.14.1 pyhd3deb0d_0 conda-forge
import holoviews as hv
from geoviews.tile_sources import tile_sources
hv.extension('bokeh')
objs=[]
for key in tile_sources:
objs.append(tile_sources[key].opts(title=key))
hv.Layout(objs).cols(3)