These are just a few links to images, presentation videos, project walkthroughs, etc., which may be useful for seeing different kinds of hand-drawn maps, certain techniques, or simply some inspiration.
Photos of some Erwin Raisz work from Harvard map collections:
https://www.dropbox.com/sh/a1v0znr2jchvbnl/AAAr4S2ce9mO7gDq2WcF67yra?dl=0
Some maps from Maptime Boston's last hand-drawn maps meetup:
http://maptimeboston.github.io/event/2015/07/15/maptime/
Ryan Sullivan:
"Cartography and the Lost Art of Drawing" (video of a NACIS talk)
https://www.pasteinplace.com/
Molly O'Halloran:
"Hand-rendered map illustration techniques" (video of a NACIS talk)
http://mollyohalloran.com/
@MollyOHalloran_
Anton Thomas:
"Drawing a Continent by Hand" (video of a NACIS talk)
"Methods of a Hand-Drawn Map" (video of a NACIS talk)
https://www.antonthomasart.com/
@AntonThomasMaps
John Nelson:
Map Made By Hand
Hillshade by Hand
https://adventuresinmapping.com
@John_M_Nelson
Sarah Bell:
https://petrichor.studio/
@sarahbellmaps (follow for updates on some hand-drawing projects)
Heather Smith:
Hand-drawn terrain (combines hand drawing and digital mapping)
Dylan Moriarty:
UW-Madison map (recreating an old hand-drawn map)
https://dylanmoriarty.github.io/
@DylanMoriarty